MODIFICATION OF THE EYE PEDUNCLES IN CYMONOMUS. 443 



following list of such modifications in deep-sea Decapoda is 

 given by Dr. Ortmanu in the fifth volume of the new issue of 

 Bronn's ' Thierreich ' (1899), parts 53, 54, and 56, p. 1191 : 



''Psalidopus, in 400 — 500 fathoms depth, has eyes 

 without pigment and without facets. 



"Some species of Pontophilus have pale pigment, but in 

 other respects well-developed eyes. 



'' Prionocrangon (200 — 500 fathoms) has no eyes. 



"All Eryonidas are blind: the eyes are reduced to a 

 stump. 



"In Phoberus the eyes are small and reduced. 



"In Thaumastocheles they are entirely gone. 



"In Nephropsis they are reduced, 



"Eiconaxius has the pigment pale (even in the deeper part 

 of the littoral zone, where it lives in the inside of sponges). 



"In Calastacus and Calocaris the eyes are devoid of 

 pigment and of facets. Among the Paguridea, Chiro- 

 platea presents only conical eye-stalks. Catapaguroides 

 microps, A. M. E. et Bouv., has degenerate eyes. 



"The sub-family Munidopsina) (five genera and many 

 species) is characterised in distinction from the Galatheiua) 

 by the reduced eyes.^ 



"Among the Dorippidse, Cymonomus is blind, and in 

 Cymonomops the eye pigment is wanting; in Ethusina — 

 in contrast with Ethusa — the eye-stalks are not capable of 

 movement, and the eyes are reduced. 



"An interesting case is presented by one of the Brachy- 

 ura, Bathyplax typhlus, A. M. E., in which, when occur- 

 ring at depths of 400 to 450 fathoms, very short eye-stalks 

 with undeveloped cornea3 are found ; whereas, in examples 

 which are taken in shallower water, the short eye-stalk 

 carries a small but distinct cornea." 



The foregoing summary, relating to the eyes of Decapoda 

 only, was published in 1899. 



The description by Dr. Norman of his Ethusa granu- 



' See ri£;s. 8 and 9. 



