176 



SCIENCE 



[Vol. IY., No. 82. 



a pamphlet entitled ' The land -system of the 

 New-England colonies,' — a work which well 

 supplements the series before us. 



THE EXPLORING VOYAGE OF THE 

 CHALLENGER. 



{Third notice.} 1 



One of the most important of all the out- 

 comes of the expedition is undoubtedly Alex- 

 ander Agassiz's memoir upon the Echinoidea 

 (vol. iii., 321 p., 45 pi.) which occupies fully 

 two-thirds of one of the massive volumes of 

 the report. Mr. Agassiz's personal acquaint- 

 ance with all known types of Echinoidea, re- 

 cent and fossil, gives him an advantage as an 

 authority over all his contemporaries ; and, 

 without some such special training, it would 

 have been a matter at least of extreme diffi- 

 cult}^ to decipher the complex relations of the 

 multitude of singular forms intermediate be- 

 tween the faunas of ancient and modern times, 

 which have been brought to light by the Chal- 

 lenger expedition. The value of these collec- 

 tions ma}' best be shown by a bit of statistics. 

 When the author's ' Revision of the Echini' was 

 publishing (1872-74), there were enumerated 

 207 species, distributed in 89 genera, including 

 2 deep-sea species discovered by the Porcu- 

 pine, and 13 by Count Pourtales. In the gen- 

 eral list which accompanies this report, there 

 are 297 species and 107 genera enumerated, 

 making, in all, 90 species and 25 genera added 

 to the former list, in spite of the reduction 

 in number by the cancelling of nominal spe- 

 cies. This shows that 80 species "of deep-sea 

 echinoids have been discovered since those 

 of Mr. Pourtales, and that fully one-third of 

 the whole number of known species of Echi- 

 noidea have been discovered since the days of 

 deep-sea dredgings. It would seem absurd to 

 attempt, in a review so limited as this, even to 

 call attention to the main points of interest in 

 a memoir of such extent as this. The most 

 instructive chapters for biologists in general, 

 however, are those upon the "character of 

 systematic affinity of allied groups of Echinoi- 

 dea " (p. 18), upon the "relations of the Ju- 

 rassic Echinoidea to the echinid faunas of the 

 present day" (p. 19), upon the " connection 

 between the cretaceous and recent echinid 

 faunas " (p. 25), and upon the " geographical 

 range of the continental and abyssal species" 

 (p. 246) ; in which latter, especially, is pur- 

 sued a line of thought of great importance to 

 all those who are considering the problems of 



1 For previous notices see Nos. 66, 79. 



the origin of marine faunas. Roetter's litho- 

 graphic delineations are especially worthy of 

 admiration. 



Another paper, especially satisfactory by 

 reason of its extent and completeness, is Col. 

 Theodore Lyman's report on the Ophiuroidea 

 (vol. v., 387 p., 48 pi.). This is a monograph 

 of all the known species (500 in number) , and 

 is illustrated by about 750 beautiful lithographic 

 figures, drawn by L. Trouvelot. Mr. Lyman's 

 introductory remarks, with his diatribes against 

 genealogical tables and theories of phylogeny, 

 will delight even those whom he intends to 

 criticise, so genial and keen is the humor with 

 which his views are expressed ; and there is 

 something refreshing, too, in the curt, sharp-cut 

 phrases in which his general conclusions are 

 formulated. Exceedingly interesting, too, is 

 the manner in which the writer has succeeded 

 in framing his diagnoses of species, genera, and 

 families, in simple words, half of them of one 

 syllable, and Anglo-Saxon in origin at that. 

 He surely has fulfilled his intention ' ' not to 

 add to the jargon in which zoology is now 

 smothering," — a jargon, he declares, " such as 

 Moliere would scarcely have ventured to put in 

 the mouth of the medical faculty in his Malade 

 imaginaire." The number of new species 

 added by the Challenger was 170, with 21 

 new genera. The tables of distribution, geo- 

 graphical, bathy metrical, and thermal, with 

 the 'brief reflections on their indications,' are 

 suggestive in many directions, and we regret 

 that the reflections may not here be quoted at 

 length. In general terms, it may be said "that 

 a ver} r large proportion of the species live 

 exclusively on the littoral zone, and that 

 therein are included species both of cold and 

 of hot water, though the number of the latter 

 is much the larger. Then there is a large 

 fauna of 50 species, which live exclusively 

 below 1,000 fathoms, and which have to endure 

 a degree of cold near to freezing, an enormous 

 water-pressure, and an entire absence of sun- 

 light. Between these extremes there are 

 large groups whose favorite, or even neces- 

 sary, habitat is restricted to given depths." 

 Sixteen genera do not go lower than 30 

 fathoms ; and they, without exception, inhabit 

 warm seas. " This proves that certain groups 

 demand a high temperature, and cannot accom- 

 modate themselves to a lower one. Should 

 any of them, therefore, be found fossil, it 

 would be reasonable to infer that the horizon 

 was a shallow covered by warm water. Nine 

 genera have not yet been found above 1,000 

 fathoms : " their occurrence, therefore, as fos- 

 sils, might denote a geological bottom of great 



