86 Dr. 0. Grimm on some Blind 



series of years in dark prisons have lost the pigment of their 

 eyes, and when brought once more into the open could not for 

 a long time distinguish objects, but rather suffered pain from 

 the daylight, as also that " in many blind people the eyes 

 have literally disappeared. In the bodies of men who were 

 perfectly blind when alive we even find that the optic nerve 

 has disappeared up to the brain, i. e. transformed into a mass 

 which contains no visual-nerve fibres " (Strieker, ' Studien fiber 

 das Bewusstsein,' p. 54). Thus it appears very natural that 

 animals which live in dark caves, wells, sea-abysses, or in 

 the earth itself should lose their power of vision, their eyes 

 being reduced to almost nothing — as, indeed, is indicated by 

 the fact that eyes are often still present although only rudi- 

 mentary, such as we find, for example, in Sorex and Talpa. 



But we know that in the depths of the sea where some eye- 

 less animals occur, whose deprivation of eyes is explained by 

 the darkness prevailing in those abysses, there also exist 

 forms which have not merely ordinary eyes, but unusually 

 developed, large, prominent, and strongly pigmented eyes. 

 Nay, the Gnathophav&ia of the ' Challenger ' Expedition, 

 coming from a depth of from 1830 to 4020 metres, actually 

 possesses pedunculate eyes, and, besides these, ocelli on the 

 maxilla? ; the Memida from a depth of 1000-1200 metres 

 has well-developed and exceedingly sensitive eyes ; while 

 Gammaracanthus caspius, mihi, from a depth of 108 fathoms 

 in the Caspian, Boechia spinosa, nasuta, and hystrix, mihi, 

 from depths of 70-150 fathoms in the Caspian, and various 

 species of Mysis from the same sea and from depths down to 

 500 fathoms, all have well- developed, large, prominent, and 

 black-pigmented eyes. This sufficiently proves that at the 

 depths indicated the visual organ can be and is made use of, 

 as here absolute darkness does not prevail, but only a dark 

 night. We have only to remember that nocturnal animals, 

 such as the owls, predacious mammals, &c, possess very large 

 and well-developed visual organs (in fact, eyes adapted to the 

 darkness) , to explain the established fact that the depths of the 

 sea are inhabited by crustaceans in which the visual faculty 

 is enormously increased. But seeing that, as has been said, 

 forms of animals also exist in the same abysses whose eyes 

 are but slightly developed or unpigmented, or even appear 

 completely reduced to a rudimentary condition, it is evident 

 that the explanation that the retrogression of the eyes is pro- 

 duced by living in the depths of the sea is not sufficient. 



In the Caspian Sea, at 0° 12' E. long, (from Baku) and 

 39° 51' N. lat., I obtained in a single cast of the dredge ten 

 new species of Gammaridas (namely Gammarus jjauxillus, G. 



