SOME NEW BOOKS. 



Faxon's " Albatross " Crustacea. 



Reports on an Exploration off the West Coasts of Mexico, Central and 

 South America, and off the Galapagos Islands, in charge of Alexander 

 Agassiz, by the U.S. Fish Commission Steamer "Albatross," during 1891, 

 Lieut. -Commander Z. L. Tanner, U.S.N., commanding. XV. — The Stalk- 

 eyed Crustacea. By Walter Faxon. Pp. 292, with sixty-seven plates (ten of 

 which are colored) and one chart. Memoirs of the Museum of Comparative 

 Zoology at Harvard College, vol. xviii. Cambridge, U.S.A. ; April, 1895. 



The artistic plates by Mr. A. M. Westergren make this volume very 

 attractive. His coloured drawings vividly suggest the beauty of 

 deep-sea crustaceans as they appear when first brought to the surface. 

 There is a certain splendour in the prevailing red tints, " which pass 

 through various shades of pink, orange, and yellow, to straw color 

 and ivory white." Some shore species are found to turn red when 

 kept in the dark ; hence Mr. Faxon is inclined to believe that in the 

 deep-sea species the prevalence of red is "due to a modification of the 

 pigments, induced by the darkness in which these creatures dwell, 

 either through chemical action or more probably through a physio- 

 logical process originating in the eye and affecting the pigment cells 

 by a reflex action. In either case the prime cause is a purely physical 

 one — the more or less complete absence of light in the depths of the 

 sea." He proceeds to infer that " this color, then, is to be regarded 

 as entirely useless to its possessor." Nevertheless, he presently 

 contrasts the free-swimming Crustacea from great depths, which are 

 " commonly of a very bright red color and endowed with visual 

 organs of a high order," with the sedentary, concealment-loving, 

 bottom species, which " are most often pale of hue and frequently 

 blind." But surely, when difference of habit is thus associated with 

 difference of colouring, it is illogical to take it for granted that 

 natural selection is unconcerned in the coincidence. 



To those who may wonder why deep-sea crustaceans should be 

 red-tinted in general rather than of any other colour, Mr. Faxon 

 gives Pouchet's explanation, that " the pigments of the xanthic series 

 (red, orange, and yellow) in Crustacea are contained in contractile 

 anatomical elements — the chromatoblasts — while the blue pigment is 

 never found in the substance of the chromatoblasts, but is held in 

 free solution." Under the influence of the abyssal darkness there is 

 supposed to be so great an expansion of the red chromatoblasts that 

 any effect from the cyanic tints is completely overpowered. 



In his Essay on the Distribution of Marine Crustacea, Mr. Faxon 

 accepts the general opinion that the chief factor governing it is the 

 temperature of the sea. He imputes inconsistency to Dana, who 

 first of all divided the waters of the globe into five zones of marine 

 life, " determined by isocrymal lines, or lines of equal mean tempera- 

 ture of the surface water during the coldest month of the year," and 

 then proceeded to base his faunal areas, except in the two polar 



