July 17, 1885.] 



SCIENCE 



55 



he does not find one which might not have 

 been expected at 100 fathoms or less. The 

 deepest haul producing any bivalve was 2,900 

 fathoms, where Callocardia was found in the 

 Pacific, and an almost exactly similar species 

 was obtained at 1,000 fathoms off the Azores, 

 in the same latitude of the Atlantic. On the 

 whole, lamellibranchs were scarce : but this 

 may have been owing to the use of the trawl 

 instead of the dredge. The greatest depth at 

 which any gastropod was found was 2,650 

 fathoms, in the South Atlantic; and this was 

 a little Sty lifer parasitic on an echinoid. The 

 fossil genus Actaeonina was a find worth hav- 

 ing ; and many, like Gaza and other trochids, 

 were of great beauty. A number of arctic 

 species were found at home in the antarctic 

 sea ; and several others seem to wander over 

 most of the world. Professor Haddon reports 

 a chiton (C. [Leptochiton] alveolus Sars) from 

 2,300 fathoms, which was the only really deep- 

 sea species found of this ancient group, though 

 several others of the same genus range over 

 300 fathoms. Among the nudibranchs, an im- 

 mense creature, Bathyfloris abyssorum of Dr. 

 Bergh, as big as a cocoanut (twelve centimetres 

 long) , forms a remarkable transition between 

 Tritoniidae and Dorididae, and was obtained at 

 2,425 fathoms. It is the largest nudibranch 

 known, and was purple, brown, and orange 

 colored when alive. Among treasures from 

 shallower water were a living Nautilus pompil- 

 ius and a partly decorticated Spirula. 



It is impossible to give an account of the 

 varied, beautiful, aberrant, or exquisite forms 

 of the Crustacea, star-fish, echinoids, and brit- 

 tle-stars which were brought up from the deep 

 sea. Their attractions for the 63^6 of the aes- 

 thete as well as of the naturalist are obvious to 

 an}' one who may examine the charming wood- 

 cuts which illustrate their form and structure. 

 The sea-lilies are among the most attractive ; 

 and yet it is hard to choose from among so 

 many any special group as, on the whole, the 

 most beautiful. 



Among the worms, decidedly the most ex- 

 traordinary is Syllis ramosa, — a creature living 

 in sponges, not satisfied with shaking off its 

 progeny by dropping sections from its tail, but 

 which actually branches in all directions later- 

 ally, and shares with these collateral relations 

 the ramifications of its stomach. In another 

 form, Genetyllis, the head is composed of little 

 more than two enormous eyes, with a large 

 median nerve-mass with which the retina of 

 each is continuous. Some worms have tubes 

 five yards long : others ornament their dwell- 

 ings with hyaline sponge spicules or spiny pro- 



cesses. They reach depths of 3,125 fathoms, 

 and range to the surface, the Serpulae and 

 Terebellae being the most noteworthy in this 

 respect. 



The consideration of the calcareous and 

 horny sponges was undertaken by Dr. N. Pole- 

 jaeff of Odessa, who, after demolishing all pre- 

 vious attempts at their classification, aptly 

 compares the systematist to a man wandering 

 in the dark, — a condition in which the sj'nopsis 

 of his memoir certainly leaves its reader. The 

 number of species was not large, and none of 

 them came from great depths, though many 

 were undescribed. The group of sponges to 

 which the beautiful Venus' s flower-basket, 

 Euplectella, belongs, offers, as might be expect- 

 ed, many new and exquisite species, which are 

 illustrated in a manner worthy of their attrac- 

 tions. Prof. F. E. Schulze reports that the 

 Challenger collection has more than doubled 

 the number of known species, which now 

 amounts to more than one hundred. The 

 tropical zone of the Pacific is the richest region, 

 eighteen species having been obtained at one 

 haul, in the vicinity of Papua ; but the largest 

 total number of species comes from the South- 

 ern Ocean. They are essential^ ab3'ssal ani- 

 mals. The richest additions to an}^ single 

 group of marine animals made hy the expedi- 

 tion were to the Radiolaria. These rhizopods 

 are now known to differ from the foraminifera 

 and heliozoa chiefly by the separation of their 

 unicellular body into an inner and an outer 

 series of constituents. With few exceptions, 

 they are remarkable for their skeletons, of the 

 most varied and delicate form, and of siliceous 

 or chitinous structure. They swim in numbers 

 at the surface, or even at great depths ; and the 

 ooze at even the greatest known depths is often 

 composed of astonishingly vast numbers of 

 their delicate skeletons. From a few hundred 

 known forms, the work of the Challenger has 

 expanded the list to several thousands, among 

 which Professor Haeckel has distinguished six 

 hundred and thirty-four genera, included in 

 twenty-four families and several orders. It 

 must, however, be borne in mind that these 

 systematic divisions are far from having the 

 zoological value of divisions similarly' styled in 

 higher groups, though here perhaps necessary 

 from the multitude of species. We have re- 

 gretted the necessity, from considerations of 

 space, for omitting references to the admirable 

 and epoch-making work of Professor Moseley 

 on the corals, confirming and extending the 

 work of the elder Agassiz, or that on the fo- 

 raminifera and diatoms, both of which exhibit 

 forms of great beauty, which are excellently 



