MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 95 



In the four previous species the eyes are not described by Bate. Said to be wanting (S. I. 

 Smith). 



Pentacheles sculptus Smith. North Atlantic, 250 to 1,081 fathoms. 



P. Icevis Bate. Pacific, 500 fathoms. 



P. suhmi Bate. Pacific, 120 fathoms. 



P. gracilis Bate. Pacific, 610 fathoms. 



P. obscurus Bate. Pacific, 1,070 fathoms. 



P. auriculatus Bate. Pacific, 610 fathoms. 



P. enthrix Bate. Pacific, 315 fathoms. 



P. validus A. M.-Edw. West Indies, 955 to 1,591 fathoms. 



P. agassizii A. M.-Edw. West Indies, 118 to 1,058 fathoms. 



P. spinosus A. M.-Edw. West Indies, 611 to 1,568 fathoms. 



In the species here mentioned the eyes appear to be essentially as in P. sculptus, where the 

 eye-stalks are without facets, but with two apparently cornea-like areas (S. I. Smith). 



P. nanus Smith. North Atlantic, 705 to 1,917 fathoms. "No colored pigment or facetted surface." 

 P. debilis Smith, North Atlantic, 1,290 to 1,309 fathoms. " Eyes nearly as in the, other species" (Smith). 

 Astaeus zaleucus is not an Astacid, and is 



Thaumastocheles zaleucus Wood-Mason, 1874. West Indies, 450 fathoms. "Eyes and eye-stalk wanting 

 , entirely." 



Nephropsis stewarti Wood-Mason. Bay of Bengal, 260 to 300 fathoms. 

 N. agassizii M.-Edw. Straits of Florida, 1,500 meters. 



X. agassizii n. sp. Wood-Mason. Andaman Island, 600 meters. In both species the eyes are rudimentary, 

 and are like small tubercles deprived of cornea? (A. M. -Edwards). 



Six or seven species of Nephropsis are now indicated, ranging over the Atlantic and Pacific 

 in 100 to 800 fathoms. They are all very closely allied or identical, and it might be best to refer 

 to the genus as a whole. 



Orophorhxjnchus sp. blind (Wood-Mason). 



Galathodes, 13 species. North Atlantic, West Iudies, and Mediterranean, 51 to 2,376 fathoms. " Eyes small, 



with incomplete cornea. " 

 Ethusina abyssieola Smith. North Atlantic. " Only a very few visual elements at the tips of the immobile 



eye-stalks" (Smith). 

 Ethusia (Ethusina) challengeri Miers. Pacific Ocean, 1,875 fathoms. 

 Pinnotheres (Semper). 

 Lyreidus vhanneri Wood-Mason. Blind. Bay of Bengal. 



Class ARACHNIDA. 

 Order Acarina. 



In the family Bdellidaa the eyes are sometimes wanting ; so also, in species of the family Ixodidee. In the Gama- 

 sidae, Oribatidae, aud Acaridae the eyes are absent. The Tardigrada are eyeless, as well as the Linguatulina. 

 Geckobia latasti Meguin. Parasitic in adult state ou a lizard (Bull. Soc. Ent. France, viii, 1878). 

 Eschatocephalus gracilipes Prauenfeld. Caves in Carniola and Hungary. 

 Eschatocephalus hispanm Schaufuss (?). Spain. 

 Eschatocephalus frauenfeldi Koch. Roseumiiller Cave, Germany. 

 Eschatocephalus seidlitzi Koch.' Cave in Franconia, Germany. All parasites on pigeons or bats. 



Order Arthrogastra. 



Chernes. All the species are blind. 



Ny( rtalope tenuicaudata Cambr. Blind, allied to Thelyphonus. Ceylon. 



Nyctalops crassicaudata Cambr. Blind, allied to Thelyphonus. Ceylon. 



Class MTRIOPODA. 



Family Scolopendridae. 



The species of Cryptops, Opistbemega, Scolopocryptops, and Newportia are eyeless; in 

 Monops there is one simple eye on each side. 



Family Geophilidae. 



All the species eyeless, or rarely with but a single pair of ocelli. 



