910 



SCIENCE. 



[N. S. Vol. III. No. 78. 



(p. ix). A brief summarj' of fche chapters 

 will enable the student to judge of the ex- 

 tent and scope of the work. 



In the first chapter, after the ' introduc- 

 tory, the form and movement of fishes, 

 their classification, geological distribution, 

 mode of evolution, [and] the survival of 

 generalized forms ' are considered (pp. 

 1-13). 



In the second chapter, ' the evolution of 

 structures characteristic of fishes, e. g. (1) 

 gills, (2) skin defences, (3) fins, and (4) 

 sense organs ' are discussed (pp. 14-56). 



In the third chapter, ' the Lampreys and 

 their allies,' including ' the Ostracoderms 

 and Palseospondylus,' are described (pp. 

 57-71). 



In the fourth chapter (pp. 72-98), 'the 

 Sharks,' in the fifth (pp. 99-115) 'the Chi- 

 mseroids,' in the sixth (pp. 116-138) 'the 

 Lung-fishes' or Dipnoans, and in the sev- 

 enth (pp. ]39-178) 'the Teleostomes (i. e.. 

 Ganoids and Teleosts)' are briefly noticed. 



In the eighth chapter (pp. 179-226) we 

 are presented with sketches of thegrouj)S of 

 fishes contrasted from the standpoint of em- 

 bryology, their eggs and breeding habits, 

 outlines of the development of Lamprey, 

 Shark, Lung-fish, Ganoid and Teleost, [and] 

 their larval development.' 



Next are furnished unnumbered sections, 

 giving 'derivation of names' (p. 227-230), 

 'bibliography' (p. 231-251), and 'explana- 

 tory tables ' (V.-XIX.) continued (p. 252- 

 283) from others given elsewhere (p. 8, 9, 

 98, 166) in the volume, which is capped 

 with a full index (p. 285-300). 



Fish is a word of diversiform meanings ; 

 it is the expression of a concrete notion and 

 it is the symbol of an abstract concept ; in 

 the former sense it brings before the mind 

 a vertebrate inhabitant of the water with a 

 subfusiform bodj', and in the latter sense 

 any inhabitant of the water as contrasted 

 with one of the air or of the land ; when it 

 is used in such compounds as fish- form. 



fish-like, fish-shaped, fish-backed and fish- 

 bellied, it is the tyj)ical fusiform fish that is 

 meant; when shell-fish, star-fish and jelly- 

 fish are named it is the abstract concept of 

 inhabitants of the water that is imagined. 

 In the latter sense it is a reminiscence of 

 the time when men believed in the ' ele- 

 ments ' of earth, water and air, and appor- 

 tioned to each their inhabitants. Those 

 inhabitants were designated by Plato as 



SrjpuTpo<pv/.a, UYpoTpo(ff/.a, and Brip(Vjiip.iy.a. In 



the cosmological dreams of elders of our 

 ' Aryan ' stock as well as the Semitic they 

 were created speciallj' for the elements in 

 question; so imagined the Hebrew histo- 

 rians, and to like purpose did Ovid sing. 



Dr. Dean well remarks that " it would be 

 unreasonable to doubt that the fish form is 

 adapted to the mechanical needs of its en- 

 vironment" (p. 6). Such adaptation is 

 evident. Xature has evolved and devel- 

 oped the form ; man has copied. The ' fish 

 form,' in its perfection, is realized in the tun- 

 nies and other wanderers of the high seas. 

 The forms whose movements are delineated 

 (p. 2) after Marey are not of this class, but 

 a stage or more removed from it. The 

 typical fish can only describe simple curves; 

 the shark with its sigmoid curve and the eel 

 with its multiplex curve introduce other 

 conditions. On the other hand, it is the 

 typical and sub-typical fish forms that have 

 been the subjects of Mr. Parson's memoir 

 on ' the displacement and the area curves 

 of fish '* and have furnished the four out- 

 lines copied by Dr. Dean (p. 5). 



The typical fish form, as exemplified in 

 the tunnies, is especiallj' adapted for rapid- 

 ity of locomotion, and all the fishes in which 

 it is developed are preeminently coursers 

 of the sea. But it is not alone by coursing 

 that fishes obtain their dailj' food. To ob- 

 tain that food, to secure safety and conceal- 

 ment, Nature has provided many devices 



* Trans. Am. Soc. Mech. Engineers Vol. IX., pp. 

 G79-G95, -with 7 pi. iuol. 21 contours. 



