great importance in the determination of species, so that the study of lichens cannot now be successfully or thoroughly prosecuted without an acquaintance with them. Their general form and

Fig. 150.

color being constant in each genus and species, they have, as Professor Tuckerman observes (Lichens of California), "added a new content to the conception of species." While their study opens fresh difficulties and perplexities to the student, it affords him a deeper insight into the inscrutable mysteries of nature,

Spermatia.

who, whatever wo may strive to ascertain, ever holds some secrets in reserve which are beyond

our grasp.

In its earliest stages the spore-case appears filled with small globular granules, in which lines of division appear, and the spores gradually assume their regular form and number. The spores are at first colorless and simple, and their internal divisions

and changes of color may be seen in all gradations in the same hymenium. They frequently remain filled with a mass of oil globules. They are sometimes arranged in a linear

series in the spore-case, sometimes irregularly grouped, and sometimes spirally twisted around a central (ideal) axis. When ripe they are expelled from the spore-case by the

Fig. 152.

pressure of the paraphyses, which when moistened, absorb water copiously. Many observations have been made as to the manner of the development of the thallus from the spore, but the matter is still involved in a good deal of obscurity.

On the thallus of most lichens are to be seen a number of small

Fig. 153.

Portion of pyenide of Biatora Heerii black dots, either scattered irregularly over its surface, or along the margin. These are the spermogonea (Fig. 148), and they contain, in great numbers, the spermatia, which are extremely minute, cylindrical, or needle-shaped bodies, situated on the extremities of simple or branched filaments, called sterigmata (Figs. 149, 153). Their forms appear to be constant in each species, but are much less diverse than those of the spores, and they are always colorless. They have been supposed to be the male organ of reproduction, but nothing is certainly known of their functions. Nylander, who attaches much importance to the spermatia in his Synopsis, distinguishes five forms of them. 1st, the acicular slightly swollen at one end, as in Usnea; 2d, acicular slightly swollen near the extremity, as in Evernia; 3d, straight acicular or cylindrical, as in most Lecanoras; 4th, bowed acicular, or cylindrical, as in some Lecanoras; 5th, ellipsoid or oblong, as in Calicium, which last, he says, approach rather too near the short cylindrical spermatia. There are no spherical spermatia. But he is not fortunate in attempting

to apply these distinctions, and it seems difficult to render them of any great systematic value. Leighton, who has described and figured the spermatia of a large number of lichens, has failed in many instances to recognize the differences in form indicated by Nylander, especially in regard to the first two forms, and points out a great confusion in the application of Nylander's idea in his Prodromous and Synopsis in regard to the spermatia of Platysma (Cetraria). In figure 150 (a, spermatia of Pyrenula lactea Mass.; b., Verrucaria epigaa Pers. ; c, Synalissa phylliscina; d, S. phœococca Tuck.; e, Lecanora athrocarpa Duby; f, Parmelia colpodes Tuck.; g, Cetraria ciliaris Ach.; h, Placodium camptidium Tuck.), we give a few additional illustrations of the different forms of spermatia. A slight but distinct crackle is almost invariably heard on crushing the spermogonia under the thin glass, which seems peculiar to these organs. Besides the spermogonia, there are also other small bodies, resembling them in external appearance, called pycnides (Fig. 151), but containing spore-like bodies called stylospores (Fig. 152), on the extremities of short filaments. They are often septate. Their office is unknown, and they are of comparatively infrequent occurrence.

REVIEWS.

THE EARED SEALS.*-Up to the year 1866, comparatively little attention had been paid to the systematic relations inter se of the seals, and in that year, Dr. John Edward Gray, in the "Catalogue of the Seals and Whales in the British Museum," adopted essentially the same classifica

*On the Eared Seals (Otariadæ), with detailed descriptions of the North Pacific species, by J. A. Allen. Together with an account of the habits of the northern fur seal (Callorhinus ursinus), by Charles Bryant. [1 pl. 108 pp., 3 pl. 31. exp.] Bulletin of the Museum of Comparative Zoology [etc.). Vol. II. No. 1.

The copy which we owe to the kindness of the author, is further illustrated by two photographic plates of Zalophus Gillespii.

tion which he had presented in 1850, in his catalogue of the seals-8 singularly unnatural one, based chiefly on the number and development of the teeth; all the Pinnipeds were regarded as forming a single family, divided among five sub-families, namely:

A. Grinders two-rooted; [etc.]*

a. cutting teeth 4 [above]; 4 [below] [etc.] Stenorhynchina.

b. 46

". 6 [above]; 4 [below] [etc.] Phocina.

B. Grinders with single root (except the two hinder grinders of Halichorus). c. Ears without any conch; [etc.].

* Muzzle large, truncated, simple; canines large; grinders lobed, when old, truncated. Trichechina (with Trichecus Rosmarus and Halichorus!)

** Muzzle of the male with a dilatable appendage; cutting teeth 4 [above] 2 [! below]; [etc.] Cystophorina.

d. Ears with a subcylindrical distinct external conch; [etc.] Arctocephalina. *Only the prime contrasted characters are noticed here; the others are often applicable only to a portion of the groups diagnosed.

If classification is really intended to represent the natural relations of organized beings, as determined by the sum of their structural agreements, and the subordination of the respective groups differentiated, a more unfortunate classification than that noticed could scarcely be devised; if even it is only regarded as a means to enable us to ascertain the name of a certain form, it is a decided failure; i. e. Halichorus (of the second prime division), having the "grinders with single root (except · the two hinder)," not being distinguished, even by Gray's own diagnosis, from Lobodon of the Stenorhynchina (first prime division), which has only the first, second, and third front upper grinders single-rooted, [the rest two hinder] two-rooted!" Like inconsistencies prevail, but why, in the name of science and common sense may we ask, is Halichorus separated from those forms which it so much resembles, to be combined with the Walrus, to which it is so very unlike, when even a diagnosis has to be explained away to admit of such a freak! The chief modifications in the arrangement of 1866, compared with that of 1850, are the introduction of the genera Pagomys, Halicyon, (the latter based on intangible characters,) and Callorhinus.

In the same year, 1866, appeared a "Prodrome of a Monograph of the Pinnipeds, by Theodore Gill," in the Proceedings of the Essex Institute (V, pp. 1-13), in which those animals were distributed among three families (Phocida, Otariida, and Rosmarida), equivalent to the three subfamilies recognized by Turner, and the Phocida were divided into three sub-families, distinguished by important osteological characteristics previously unnoticed by systematists. In the Otariidæ, five genera were recognized, of which the types were the only species mentioned.

This article was rapidly succeeded by a number of memoirs, chiefly on the Otariids, two by Gray and two by Peters being published in the same year. The former, after a first passionate outburst of anger, finally accepted as valid the three families just noted, and, like Peters, adopted the genera of Otariids first defined in the Prodrome (i. e. Eumetopias and

Zalophus), raised to generic rank two additional groups named as subgenera by Peters, and ended by proposing genera for every recognized species of the family, and distributing them among five sub-families. The extreme to which differentiation was carried may be judged from the fact that Mr. Allen has reduced two of his genera to one species, and was strongly inclined to reduce three others to a second species. Those sub-families in the main agreed with the genera defined in the "Prodrome of the Pinnipeds," but were rendered unnatural by the combination - in face of the characters used as diagnostic― of Arctophoca (a sub-division of Arctocephalus) with Eumetopias, and by the association of Phocarctos (a form inseparable from Otaria) in the "Arctocephalina." As an example of the mode of differentiation, the following diagnoses will suffice.

"Zalophus. Grinders large and thick, in a close uniform series. South America."

"Nerphoca. Grinders large, thick, all equal, in a continuous uniform

series. Australia."

As will be perceived, the same feature is indicated simply by a slightly different phraseology, save as to the locality. But even the alleged character of locality is erroneous, for Zalophus has never been found in South America, and its type is an inhabitant of the North Pacific only, i. e. California and Japan!

The chief and most valuable information published after the "Prodrome," and up to the year 1870, was contributed by Dr. Wilhelm Peters, and to that accomplished zoologist we are indebted for the first reliable coördination of external and osteological characters- a task that was found to be impossible with the material possessed by the author of the "Prodrome."

Much information had also accumulated as to the distribution, habits, and external characteristics of the various species of Otariide, and excellent figures of the skulls of several species had been published. It was with these additional facilities that Mr. J. A. Allen proceeded to the investigation of the North Pacific species of the family, and incidentally of the classification of the entire group. He has, like his immediate predecessors, admitted the validity of the family called by him " Otariadæ," and has admirably contrasted the characteristics of the pelvis and hind limbs of those animals, with the corresponding parts of the Phocids; the species of Otariids are distributed among five genera corresponding to those established in the "Prodrome,” and of which our author remarks that "these appear to be natural groups, of true generic rank, and properly restricted; and, after a careful examination of the subject, they appear to [him] to include all the natural genera of the family." These five genera are considered by Mr. Allen as separable among two sub-families, the author remarking (p. 22) "that if the Otariado constitute a group entitled to family rank, and the so-called sub-families of the

* Allen, op. cit., p. 38.