808 



SCIENCE 



[N. S. Vol. XXX. No. 779 



Dr. Eigenmann has combined in this one 

 work the results of his various papers on the 

 cave vertebrates of America. The title is 

 slightly misleading, as he includes blind verte- 

 brates which do not inhabit caves. He also 

 includes the results of others vsfho have been 

 interested in the study of blind vertebrates. 

 It is a very comprehensive work dealing with 

 species distributed over the greater part of the 

 United States from the Pacific to the Atlantic 

 and as far south as Cuba, the West Indies and 

 northern portion of South America. 



The main bulk of the work is upon the eye 

 as affected by the absence of light. However, 

 he devotes considerable space to morphological, 

 zoological and physiological points of interest 

 in connection with the animals studied. The 

 other special senses were experimented vapon 

 and studied in some detail. The embryology 

 of some forms was studied with special refer- 

 ence to the development of the eye. 



After a short introduction he devotes con- 

 siderable space to a general consideration of 

 caves and cave fauna. In this he deals with 

 the relation of caves to the rest of the uni- 

 verse; the environment of caves; the origin 

 and distribution of cave animals; the food 

 supply; the relation of the age of caves to the 

 variety of cave fauna; the tendency to di- 

 vergence in epigean fishes and convergence in 

 cave forms. 



As to the origin of cave fauna, he holds that 

 only those forms which are negatively helio- 

 tropie or positively stereotropic are able to 

 adapt themselves to cave life; that species de- 

 pending on sight for procuring food can not 

 adapt themselves to the environment of the 

 cave. The cave fauna is not the result of 

 accidental entrance of epigean forms. The 

 aquatic cave fauna has developed from those 

 forms adapted to live in dark and secluded 

 places following the stream as it has gradu- 

 ally through ages formed subterranean chan- 

 nels. The non-aquatic forms are of more 

 recent origin and have migrated into the caves 

 after their formation. These are gradually 

 adapting themselves to the more remote parts 

 of the caves. 



The author then takes up in detail the blind 

 and cave vertebrates and their eyes. This 

 comprises the main part of the work, consist- 

 ing of 210 pages illustrated by 29 full-page 

 plates and 72 text figures. Although, with the 

 exception of birds, all classes of vertebrates are 

 represented by species having degenerate eyes, 

 by far the greatest number is found in fishes 

 and fish-like vertebrates. 



Only two species of mammals are described 

 — ^the common mole and the cave rat. The 

 former has very degenerate eyes, while in the 

 latter the eyes are practically normal and re- 

 semble very closely those of the common gray 

 rat. 



Of the amphibians only four species of sala- 

 manders are described as inhabiting caves. 

 Three are from the caves of the Mississippi 

 valley, the fourth is from the underground 

 streams near San Marcos, Texas. Detailed 

 descriptions of these eyes are given. 



Three reptiles are described: Amphishwna 

 punctata, a blind legless lizard from Cuba; 

 Rhineura fioridana, a legless burrowing lizard 

 from Florida; and Typhlops lumbricalis, a 

 blind snake found generally distributed in the 

 West Indies and Guiana. 



After a brief description of the eye of a fish 

 (Zygonectes notatus) having normal vision 

 and closely related to the blind fishes, he be- 

 gins a detailed description of the different 

 species of blind fishes. Although special 

 reference is given to the eye, he treats of 

 such general topics as general habits, respira- 

 tion, reactions to light, tactile organs, the ear, 

 anatomy of different organs, reproduction, etc. 



He describes the development of Amblyopsis 

 from the egg, being successful in rearing one 

 to the age of ten months. He corrects the 

 erroneous idea that Amhlyopsis is viviparous. 

 The mother deposits the eggs in the gill clefts, 

 where they are retained during development 

 till the young reach a length of about 10 mm. 

 and the yolk is mostly absorbed. 



Tactile organs are extremely well developed 

 and these take the place of the lost visual 

 sense. The ear is normal. In regard to their 

 power of hearing, he says: 



... if we define hearing to be the sensation 



