end of a sarcodic filament from the object to which it had, perhaps by some suctorial power, been attached.

Bdelloidina aggregata seems to approach nearest in form to Peneroplis, on account of the chambers being all on the same plane, continuous or uninterrupted by transverse partitions, linear in form and tending more or less to a spiral arrangement, with septa regularly perforated from one end to the other by holes of intercameral communication (figs. 4 and 5)--and perhaps by a disposition of the rugæ (which hang in prominent relief from the roof) to assume in some parts a transverse course, viz. across the chamber; although this would make it more like Orbiculina adunca, especially as, in some instances, there is also a tendency to a double row of holes in the septum. But from what has been above stated it will be seen that its general form is not near so like Peneroplis or Orbiculina adunca as Lituola canariensis is like Nonionina; while the uneven form and size of the sand-grains and consequent irregularity of the cavities both in Lituola canariensis and Bdelloidina aggregata are much the same, although the former is rusty and composed of quartzose sand &c., while the latter is colourless and composed of calcareous sand &c. Then it should be remembered that, as all the vitreous species of a genus are not represented by arenaceous forms, so there may be some of the latter which as yet have found no vitreous representatives: perhaps Rhabdammina and Astrorhiza may belong to the latter.

Since the above was written I have mounted a piece of Bdelloidina aggregata in which both the outer and inner surfaces of the chamber are uninjured, and can see the openings of the "labyrinthic" canals on the surface, both through the latter and through the former, by transmitted light. They are extremely minute, and situated deeply in among the minuter surface-particles, where they cannot be distinguished by reflected light any more than through the internal openings of the roof, and by testing with the direction of the light can be proved to be not owing to facet-reflection of any of 'the arenaceous particles. So this settles the question as far as Bdelloidina is concerned; and B. aggregata being exactly like Lituola canariensis in sandy composition and structure, it may fairly be assumed that all the Arenaceous Foraminifera have pores on the surface, and therefore that the "suborder," so far as it depends on imperforation, is exploded; while thus to separate animals, merely because they happen to construct their tests of foreign particles instead of calcareous material secreted by their own bodies, or both together, would be absurd.

EXPLANATION OF PLATE XIII. (figs. 1-8).

Fig. 1. Bdelloidina aggregata, n. gen. et sp., on a portion of Siderastræa, magnified four diameters. a, convex margin of the last chamber, along which are arranged the "pseudopodial apertures" (see fig. 5, a); b, lines marking the septal limits of the chambers respectively. Diagram.

Fig. 2. The same: square indicating natural size.

Fig. 3. The same portion of surface, magnified to show arenaceous composition of the test. Scale 1-48th inch to 1-1800th inch. Fig. 4. The same: horizontal section of two chambers (upper half), to show-a, septum between the two chambers; bb, holes of intercameral communication in the septa; cc, roof of chambers respectively, and internal pore-canal openings analogous to those in the shell of Nummulites. Same scale. Diagram.

Fig. 5. The same: vertical section of a chamber longitudinally, to show: -a, holes of intercameral communication through the septum ; b, pore-tubulation ("labyrinthic structure") of the roof or upper wall of the chamber; c, basal wall or floor. Same scale. Diagram. Fig. 6. The same: transverse section of the chamber vertically, showing:-a, cavity; b, walls; c, pore-tubulation or "labyrinthic structure." Same scale. Diagram.

Fig. 7. The same: portion of fig. 5 more magnified, to show:-a, septum; b, hole of intercameral communication; c, basal wall or floor; d, roof of chamber; e, pore-tubulation or "labyrinthic structure" amidst the sand-grains of the upper wall or roof; f, dark line indicative of the sarcodic layer. Diagram.

Fig. 8. The same: portion of fig. 4, c c, more magnified, to show that the pore-canal openings are deeply sunk in the interstices of reticulated rugæ pendent from the roof. a, rugæ; b, pore-canal openings.

XVI.-On the Locality of Carpenteria balaniformis, with Description of a new Species and other Foraminifera found in and about Tubipora musica. By H. J. CARTER, F.R.S.

&c.

[Plate XIII. figs. 9-15.]

In my paper on the Polytremata (Ann. & Mag. Nat. Hist. 1876, vol. xvii. p. 199) the following statement is made respecting the habitat and locality of Polytrema balaniforme Carpenteria balaniformis, viz. :

=

"Hab. Marine, on the valves of Mytilicardia calyculata and other objects, viz. Pecten, Porites, &c.

"Loc. West Indies? Indian Ocean."

"West Indies" was conjectural; and although I have every reason for concluding that the Mytilicardia on which my specimen of P. balaniforme had grown had come off a sponge, it was equally conjectural where that sponge had come from originally.

I now find, however, that the type specimens of Polytrema balaniforme in the British Museum partly cover both valves of Mytilicardia variegata in company with Polytrema miniaceum, labelled " Carpenteria, Philippines."

There is also another specimen on one valve only of a M. variegata; and this, too, is in company with specimens of Polytrema miniaceum. It is labelled "Dujardinia, Mediter

ranean.

Going to "Case 38" in the Shell-Room, we there find one specimen of Mytilicardia variegata with nothing upon it (it may have been cleaned)-and next to it a specimen from "Port Essington" (north coast of Australia), apparently bearing only the remains of P. balaniforme.

Close by may also be seen a specimen of Mytilicardia calyculata, labelled "Port Natal and Mediterranean;" and in the drawer below, a specimen of Mytilicardia variegata covered with Polytrema miniaceum, but no P. balaniforme,-labelled "Red Sea."

Following Chenu's representations, I have stated that my specimens of Polytrema balaniforme are on Mytilicardia calyculata; but I can see no difference between Chenu's figure of M. calyculata (Manuel de Conchyliologie,' 1862, t. ii. p. 135, fig. 650) and my own specimen of this bivalve, which, again, is identical with that in the British Museum labelled Mytilicardia variegata; yet the difference between this and M. calyculata in the British Museum is very evident, although not very great.

In the drawer of the Case mentioned is another specimen of M. variegata covered with Polytrema miniaceum, labelled "Port Essington;" and a crab-claw submitted for my examination by Dr. Carpenter is also in the same state, but bearing among the specimens of P. miniaceum also one of P. balaniforme.

My inference, then, altogether is, that we should seek for specimens of Polytrema balaniforme on Mytilicardia variegata &c. from the Polynesian Seas.

It may be questioned whether P. balaniforme exists in the Mediterranean Sea, although P. miniaceum is abundant there and apparently in every sea within the parallels of 35° north and south of the equator.

From what has been above stated, the presence of P. miniaceum, on account of its red colour, might prove serviceable in finding out specimens of P. balaniforme, which, being colourless and very like a Balanus, are equally likely to escape notice, since the habitat of the latter is not confined to Mytilicardia variegata in the Polynesian Seas, but, according to the late Dr.

J. E. Gray, may be on Porites, Cardita, or Pecten (Proc. Zool. Soc. 1858, pt. xxvi. p. 266).

How far the specimen labelled "Dujardinia" above mentioned, on Mytilicardia variegata "from the Mediterranean,' may be entitled to the generic distinction given to it by Dr. Gray (op. et loc. cit.), when it appears to me to differ only from P. balaniforme in the irregularity and obliquity of the reticulation on its surface, is a question which is thus answered. At the same time, while it appears to me to be only a variety of P. balaniforme, and I have stated that in all probability the latter is not to be found in the Mediterranean, even if Mytilicardia variegata exists there, the fact of the two having come from the Mediterranean is doubly doubtful.

(When desirous of obtaining the localities of the various specimens of sponges in the British Museum, the late Dr. Gray said to me, "You cannot depend for this on the statement in the Register;' for in many instances they have been purchased from 'dealers' or at sales." Certainly it is a great thing to know what does exist in the world; but the next wish is to know where it comes from, which hitherto has been too much neglected.)

After the foregoing observations on Polytrema balaniforme =Carpenteria balaniformis had been written, my kind friend, Mr. W. Vicary, of Exeter, lent me for examination a large globular specimen of Tubipora musica about as big as a man's head, said to have originally come from Australia, in and about which I found specimens of several species of Foraminifera, one of which, growing on the Tubipora itself, was so like Polytrema balaniforme that it was impossible to view it otherwise than as a species of this genus. Having resolved to describe and illustrate this species, it became necessary to name it; and in so doing the attempt to substitute "Polytrema" for " Carpenteria,' made in my paper on the Polytremata, in the Ann. & Mag. Nat. Hist. of 1876 (vol. xvii. p. 201), for the reasons therein mentioned, proved to be attended by so many difficulties that I determined to revert to the old name of "Carpenteria" given to this Foraminifer by the late Dr. J. E. Gray (Proc. Zool. Soc. 1. c.), still retaining it in the family of Polytremata, and, thus abandoning that of "Polytrema balaniforme" for "Carpenteria balaniformis," to make the new Foraminifer a species of this genus under the name of Carpenteria monticularis, which will now be described.

Carpenteria monticularis, n. sp. (Plate XIII. figs. 9-12.) Monticular, with furrowed sides, jagged circumference and apertural apex; sessile. Composition calcareous, homogeneous

(fig. 9, ab). Colourless, translucent. Surface even, uniformly. covered with pores, traversed by longitudinal grooves extending from the summit to the circumference, indicating the limits of the chambers respectively (fig. 9 d). Aperture at the apex large, ear-shaped or spiral (fig. 9, cc), leading to a vertical columella, around which the chambers are situated, and into which they open alternately one after another, as they are successively developed on a spirally inclined plane extending from the base to the summit of the test. Chambers sac-shaped, conical, cylindrical or branched, dendriform (fig. 9, b), varying greatly in size, form, and arrangement; uniformly traversed throughout by large pore-tubes more or less closely approximated (fig. 12); chamber smooth within, often presenting outside, on old specimens, a raised network in relief, dividing the surface into an oblique reticulation whose interstices are irregular in size and shape. Size about one sixth inch in diameter; aperture about 1-60th to 1-30th inch in its longest diameter. Pore-tube about 1-1800th inch in diameter, varying in length with the thickness of the chamber-wall; pore itself about 1-5400th inch in diameter, or one third of that of the tube.

Hab. Marine. Growing on Tubipora musica and Sideras

træa.

Loc. ? Australia &c.

Obs. The chief distinguishing character between this and Carpenteria balaniformis is the presence of the reticular framework in the substance of the shell or chamber-wall of the latter, within whose circular interstices the pore-tubes, although general at first, are subsequently circumscribed (fig. 13, a, b); while in C. monticularis there is no such framework, and therefore the pores are dispersed generally and uniformly throughout the structure (fig. 12). The oblique reticulation "in relief" appears to be only in old specimens, as before mentioned. It differs from Polytrema utriculare chiefly in the latter having a separate aperture to each chamber. The genus termed "Dujardinia" by Dr. Gray (op. et loc. cit.) appears to be a specimen of Carpenteria balaniformis on Mytilicardia variegata with this kind of oblique surface-reticulation, as above mentioned. So, perhaps, when more is known about this interesting genus, all these forms, including Polytrema utriculare, may be found to run into each other inseparably; for the illustrations, viz. fig. 9, a, b, given of Carpenteria monticularis are by no means representative of all the specimens that I possess, which for the most part are extremely irregular in form.

The varieties in which the chambers are branched or dendriform in their outer two thirds (fig. 9, b) very much resemble