Literary Notices. 283 



"The larvae, though not progressing continuously as individuals, form 

 a swarm which nevertheless progresses, one way and another, with 

 many internal irregularities. The movement reminds one of the in- 

 definite flowing movements of an Amoeba, in which pseudopods are 

 put out this way and that and often withdrawn, but the animal as a 

 whole progresses definitely." This swarm formation and movement is 

 a most interesting phenomenon and presents a number of problems 

 deserving of further study. Particularly interesting would be an ex- 

 perimental analysis of the reflexes and reactions of the individual larvae 

 which result in the composite swarm effect when large numbers of in- 

 dividuals are massed together. 



When the swarm of larvae leaves the nest it follows the male, ap- 

 parently by scent. When separated from the male the schools of 

 larvae do not make progressive movements as a whole, but circle 

 about in the same spot until the male comes back. The larvae at this 

 stage do not respond to a mechanical shock in the water, but at a later 

 stage, when they have taken on bright colors and are from 30 to 40 

 mm. long, the schools respond very (juickly to mechanical shock by 

 scattering and hiding in the plant material at the bottom. The light 

 reaction (negative to strong intensities) is more pronounced in the 

 older, bright colored larvae. As the larvae grow larger the schools are 

 less closely guarded by the males, and finally when they are about 100 

 mm. in length the schools probably disperse. 



The paper is illustrated by a finely executed plate showing the 

 coloration of Amia at three different stages in its life history. 



R. P. 



Eigenmann, C. H. The Eyes of the Blind Vertebrates of North America. V. 

 The History of the Eye of the Blind Fish Amblyopsis from its Appearance to 

 its Disintegration in Old Age. Article IX, pp. 167-204, pis. 12-15. 



In this, the fifth of his interesting contributions to the subject, 

 Professor Eigenmann gives a detailed account of the development of 

 the eye of the cave fish Amblyopsis . The eggs of this species are of 

 large size and carried in the gill chamber until the embryos are 10 mm. 

 in length. Egg bearing females were taken in March and April. The 

 object of the l-esearch was to compare the development of degenerate 

 and of normal eyes, and to determine (i) whether the development of 

 the degenerate organs is direct or palingenetic, (2) whether there is a 

 constant ratio between the extent and degree of phylogenetic and onto- 

 genetic degeneration, (3) the causes leading to these degenerative 

 changes, and (4) whether there is evidence that rudimentary organs are 

 retained by the embryo because they are of use to it, although useless 



