C. S. Minot. He finds that these worms (Turbellaria) are much more highly organized than is usually supposed. It has been frequently stated that some or all parts of these worms are formed by a protoplasmic substance, and not of cells, and a relationship with the Infusoria has therefore been supposed to exist. Minot finds, however, that all the tissues in the forms he studied are composed of cells, as had been stated previously by several observers. Minot finds that the parenchym, which about a year ago was not supposed to be cellular, is, in the twenty different species he studied, "mainly composed of ramified stellate cells, whose processes intertwine and unite adjacent cells." These worms are hermaphroditic, and Minot describes the egg-food stock or yolk-gland which he has discovered in the flat worms. This gland "produces cells, which remain alive, and pass down a separate duct that ultimately joins the oviduct. The cells are then thrown together with an egg-cell, and the whole cluster of cells is covered over by a shell. The egg as laid consists of the egg proper and the food-cells which are used up to nourish the egg as it grows. This curious economy is unknown outside of the Plathelminths." Minot unites the Trematode (flukes) and Cestode worms (tapeworms) into one group, under the name of Vaginiferæ. In its more extended form the paper is published, with five excellent plates, in Semper's "Arbeiten aus dem Zoologisch-Zootomischen Institut in Würzburg," an abstract appearing in the Proceedings of the Boston Society of Natural History.

The anatomy of a singular worm (Phascolion strombi) is figured and described by Théel in the Swedish Transactions.

Mr. H. N. Moseley, naturalist on board the Challenger dur ing her three years' cruise, has given an account of two new and remarkable species of deep-sea Ascidians. One of them, Hybythius calycodes, was brought up from the North Pacific from a depth of 2900 fathoms. It is stalked and cup-shaped, and is believed to be allied to Boltenia. It differs from that genus, however, in possessing a series of cartilaginous plates. symmetrically developed in the soft test. The second species, Octanemus bythius, was brought up from a depth of 1070 fathoms. It is star-shaped, with eight rays. The gill sac is

nearly absent in it, and the usual gill net-work entirely so. Muscular prolongations of the tunic run into the curious conical protuberances of the test. The nucleus is contracted and small, like that of Salpa. This singular species is believed to be without living allies.

Professor Semper has published an interesting volume upon the supposed homologies in the structure of articulated animals and vertebrates.

Echinoderms.

Among recent contributions to the developmental history of animals is a paper on the development of a sea-cucumber (Cucumaria doliolum). After fecundation the nucleus diminishes, and becomes a mere drop of protoplasm, inside which a germinal speck appears in an hour or two. The segmentation of the yolk goes on until two hundred and fifty cylindrical flagellate cells are formed. After the formation of the single-layered blastoderm, the embryo breaks through the egg-skin, and swims freely by means of its ciliated membrane. As the flagella gradually disappear, its activity is reduced to a backward and forward motion; and when the tentacles are protruded, it sinks to the ground, and moves. only by crawling.

Important papers on the anatomy of the sea stars and urchins have been published by R. Teuscher in the Jena Zeitschrift, illustrated by excellent plates. The last number contains a useful résumé of his researches on the circulatory, water, and nervous systems, and on the integument. Dr. Carpenter has studied the structure of the Comatula star-fish, with a note on the nervous system and muscles of the sea-urchins.

Professor Loven, of Stockholm, has published in the Transactions of the Swedish Academy an elaborate work, in quarto, on the Sea-urchins (Echinoids), which is illustrated by an atlas of fifty-three plates. The work is mostly taken up with an account of the hard parts forming the shell of the Echinus, but also contains an account of certain bodies called sphæridia, and an elaborate drawing and explanation of the nervous and water - vascular systems of Brissopsis lyrifera, greatly advancing our knowledge of the anatomy of these animals.

Mollusks.

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In a recent lecture on the forms of passage between the Annelids and Mollusks, Professor Perrier seems to adopt the idea, already suggested by two or three naturalists, that the Mollusks are in reality, to use Perrier's own words, worms condensed into two or three segments." Is this the beginning of the end, and are we finally to regard the Mollusks as originally descended from worm-like forms, and therefore as not forming a distinct sub-kingdom of animals?

The anatomy of the common mussel (Mytilus edulis) is elaborately treated by A. Sabatier in the Annales des Sciences Naturelles. The essay fills 132 pages, and is illustrated by nine folding plates.

In an essay on the Pliocene fresh-water shells of Southern Austria, by Dr. Neumayr and Herr Paul, the authors describe numerous modifications of the genus Vivipara, or Paludina, which occur in prodigious abundance throughout the whole series of fresh-water strata. Of this genus there are forty distinct forms (Dr. Neumayr very properly hesitates to call them all species), which are named and described in this monograph, and between which, as the authors show, many connecting links, clearly illustrating the mode of derivation of the newer from the older types, have been detected. The authors, remarks Mr. J. W. Judd, in Nature, have demonstrated that the species with highly complicated ornamentation were variously derived by descent-the lines of which are in most cases perfectly clear and obvious-from the simple and unornamented Vivipara achatinoides of the Congerien-Schichten, which underlies the Paludina beds. Some of these forms have been regarded as types of a distinct genus (Tulotoma) by Sandberger. "And hence we are led to the conclusion that a vast number of forms certainly exhibiting specific distinctions, and, according to some naturalists, differences even entitled to be regarded as of generic value, have all a common ancestry."

Dr. J. W. Dawson writes to Nature that he has found at the South Joggins coal-mines, in Nova Scotia, a number of well-preserved shells of Pupa vetusta, the oldest of land shells. It appears that this little shell is found at the bottom and top of beds 2000 feet in thickness, including many

beds of coal, and nearly the whole thickness of the productive coal measures. Conulus priscus, the only other land snail found in this section, on the other hand, occurs only, so far as known, in the lowest of the beds above mentioned. Two other Carboniferous shells, Pupa vermilionensis and Dawsonella Meeki of Bradley, have been found in the coalbeds of Illinois. All these forms belong to generic or subgeneric types still represented in America.

A list of the fresh-water and land shells of Alabama by Dr. James Lewis appears in Dr. E. A. Smith's report on the geology of Alabama for 1876. This state is remarkably rich in Unionidæ and Melanians.

Crustaceans.

We had occasion only a short time ago to notice an elaborate work by Professor Weismann on the theory of descent, and now comes an octavo of nearly two hundred pages on the natural history of the Daphnia and its allies, the "waterfleas," so common in fresh-water pools. One chapter is on the formation of the egg in the Daphnoids, another on the dependence of the embryonal development on the germinal fluid of the mother; while the last is on the influence of conception on the production of winter eggs. As a contribution to the physiology of reproduction, the essay is of a high order of merit.

Researches on the mode of respiration in certain crabs, by M. Jobert, and a note on two new species of Crustacea from New Zealand, by A. Milne-Edwards, appear in the Annales des Sciences Naturelles.

An eyeless crustacean (Niphargus puteanus) inhabiting the Swiss lakes has been minutely described by M. Humbert, who believes it to be an ancient genus, descending from a form which is now extinct, thus corresponding with Proteus, Anophthalmus, and other cave animals. He says, if we suppose that the genus Niphargus appeared before the ice period, it is impossible to say anything with regard to its place of origin; but he believes that it has really originated from forms inhabiting subterranean waters, and which became acclimatized at depths where they found the darkness sufficiently intense. The lake species, he thinks, are living under greater disadvantages than the cave species, and are suffering, as it were, from atrophy.

In a late memoir on the fauna of water deprived of light, M. Ph. de Rougemont, in his studies on the crustaceans Gammarus puteanus and Asellus Sieboldii, also the snail Hydrobius, brings out the fact of the excessive development of the organs of smell in these animals, in which the eye is either absent or very rudimentary.

The external anatomy of a shelled phyllopod (Estheria californica Pack.) forms the subject of an essay by Dr. H. Lenz. A number of new North American phyllopod crustaceans are described by Packard in Hayden's Bulletin of the United States Geological Survey (Vol. III., No. 1). It appears that the genus Lepidurus is better represented in Western and Arctic North America than in any other part of the world so far as known, there being two Western American and one Arctic American species. No species of Apus or Lepidurus occurs east of the Mississippi valley, and all these phyllopods occur mostly in the Western States. Several new entomostracous crustaceans from Colorado are described by Mr. V. T. Chambers in the same Bulletin.

The crustacean fauna of Lake Titicaca itself is very meagre. Except a species of Cypris, all the specimens collected belong to one amphipodous genus, Allorchestes, which had hitherto afforded but one or two authentic fresh-water species, ranging from Maine to Oregon and the Strait of Magellan. Seven new species are described in this paper from Lake Titicaca. Several are remarkable for their abnormally developed epimeral and tergal spines. Some are also noteworthy as comparatively deep-water forms of a family commonly regarded as pre-eminently littoral. Some of the species occurred as far down as 68 fathoms, the greatest depth of the lake being 154 fathoms. The marine species usually inhabit the shore above low-water mark, and the previously described fresh-water species are found in the shallow water of brooks, pools, or edges of lakes. No strictly fresh-water Orchestidae, the family to which these Crustacea belong, have been reported from the Eastern continent, although a few terrestrial forms are described, says Mr. Faxon, as inhabiting moist soil away from the sea.

The fresh-water Crustacea of Illinois have been enumerated and new forms described by Mr. S. A. Forbes in the Bulletin of the Illinois Museum of Natural History, No. 1. A num