250 



SCIENCE. 



[Vol. VII., No. 162 



enormous size of the eggs of one of the species 

 of Stylocheiron here described. 



The Mysidae were far better known than the 

 other Schizopoda, and the account of the Chal- 

 lenger species is consequently less important than 

 that of the other families ; still sixteen species 

 belonging to nine genera are described. A short 

 appendix contains descriptions of four ecto- and 

 two endo-parasites of species described in the re- 

 port. 



The fact that the work was written in a lan- 

 guage foreign to the author is scarcely noticeable, 

 and errors are rare. A few mistakes have re- 

 sulted from changes and additions during the 

 progress of the work, as the failure to change 

 the generic name of Amblyops australis on p. 12, 

 and the incorrect statement of the number of 

 genera and species on pp. 63 and 172. 



The numerous excellent plates bear the impress 

 of a Stockholm lithographer, and add to the in- 

 ternational character of the work. 



S. I. Smith. 



Lamdlibranchiata (vol. xiii.). By Edgar A. Smith. 

 London, Government, 1885. 4°. 



The report on the bivalve mollusks consists al- 

 most exclusively of a list of the various species 

 comprised in the collection, with such remarks as 

 appeared to be of interest, and of the descriptions 

 and figures of the species new to science. The 

 anatomical work on those species of which the 

 soft parts were preserved has been placed in other 

 hands, and is not yet published. The Rev. R. 

 Boog Watson retains the gastropods and solen- 

 oconchs, but, after doing certain preliminary 

 work, concluded to relinquish the present group, 

 which was very appropriately placed in the hands 

 of Mr. Smith, well known to all students of the 

 invertebrates as the courteous and hard-working 

 assistant in charge of the Mollusca of the British 

 museum. 



The Challenger collection of lamellibranchs 

 was obtained from the dredgings at some hundred 

 and fifteen stations, and comprises about five 

 hundred species, of which four hundred and 

 fifteen were found in water less than two hun- 

 dred fathoms deep, nine in water over two 

 thousand fathoms deep, and the remainder at 

 intermediate depths. The greater part of the 

 collection, therefore, is not of an abyssal char- 

 acter, and, in fact, forms an important contri- 

 bution to the fauna of the Southern Ocean, and 

 especially Australian waters ; but the portion re- 

 lating to the deep-sea forms is, of course, the 

 most interesting and biologically most important, 

 and will prove indispensable to all students of 

 that branch of biology. The plates are excellent. 



and the proof-reading good, though we notice the 

 references to plate vii., in the text, all read plate 

 viii. A few species which came in at the last 

 moment are represented by woodcuts in the text. 



The collection shows that no special student of 

 the Mollusca accompanied the expedition ; for the 

 opportunities were so great, that a qualified col- 

 lector would certainly have done much better, 

 both as to the number of species collected and 

 in regard to their biography. It must be remem- 

 bered that the Challenger party worked with 

 much less perfect instruments and methods than 

 are at present available, and that the loss of time 

 incurred by the use of rope in dredging is doubt- 

 less accountable for the w T ashing-out of many 

 valuable specimens which actually got into their 

 dredges. Mr. Smith is quite conservative in his 

 estimation of what constitutes a genus, but we 

 are inclined to agree in his decision that only one 

 new generic group is represented in the collection. 

 This is called Silenia, and is distinguished from 

 Lyonsiella by both anatomical and conchological 

 characters. It was found in the deep water of 

 the South Atlantic. The general considerations 

 of the report are brief. The remarkable sporadic 

 appearance of several forms in widely separated 

 localities (Red Sea and Fiji Islands, Canaries and 

 North Pacific, Australia and West Indies, and the 

 like) is instructively commented upon, though 

 perhaps none of the cases are more remarkable 

 than the recent discovery of Pecten pleuronectes 

 by the U. S. fish commission in the West Indies. 

 The wide bathymetrical distribution of certain 

 species, shown for the West Indies in the pre- 

 liminary notes on the Blake mollusks, is fully 

 confirmed for other regions by the Challenger 

 collection ; e.g., Lima multicostata in two thou- 

 sand and in one thousand and seventy-five fath- 

 oms. Neaera, Area, and Amussium were among 

 the most frequent and most characteristic forms 

 of the deeper water. Callocardia appeared in 

 very deep water, in about the same latitude, in 

 both the Atlantic and Pacific. On the whole, 

 Mr. Smith concludes that the lamellibranchiate 

 fauna of the deeps possesses no special or extraor- 

 dinary character. The species are fewer than in 

 shallower water, and new or peculiar forms are 

 still more exceptional. No special modification 

 of color, epidermis, or weight, seems to be corre- 

 lated with existence in the benthal /one: for 

 most of the species found there belong to 

 genera whose representatives are thin and pale, 

 whether they are found in deep or shallow water. 

 A tabular exhibit of the distribution in depth 

 and area, of the deep- water species, would have 

 been a valuable addition to the report, which has 

 an excellent index to the text and plates. 



