458 E. EAY LANKESTER. 



Since the present memoir was completed my attention has 

 been drawn to an article in the ' Biolog. Centralblatt/ August, 

 1903, written by Mr. F. Doflein, on ^'The Eyes of Deep Sea 

 Crabs." The article contains interesting observations on the 

 microscopic structure of the more or less degenerate eyes of 

 certain species. I have already inserted above a reference 

 to Mr. Doflein's description of the more and the less degene- 

 rate condition of the ommatidia in specimens of Cyclo- 

 dorippe unci f era from deeper and shallower waters. Mr. 

 Doflein makes some remarks upon Cymonomns granu- 

 latus, Norm., of which he figures an eye peduncle taken 



Fig. 11. — Rostrum and eye peduncles of a species of Cymononius, 

 dredged by the " Valdivia " off the east coast of Africa. Repro- 

 duced from Doflein. 



from a Mediterranean specimen communicated to him by 

 Prof. Bouvier. He also gives a drawing, reproduced here 

 (text-fig. 11), of the rostrum and ocular peduncles of a 

 Cymonomns taken (a single example) on the East African 

 coast by the Valdivia Expedition at a depth of 1000 metres. 

 Mr. Doflein refers this specimen to Cymonomns granu- 

 latus, and considers it to be a form of that species with 

 degenerate eyes. 



It seems to me, from the drawing given and here re- 

 produced, that this East African Cymonomns is much 

 nearer to Cymonomns quadrat us than it is to C. 

 granulatus. The ocular peduncles are in the condition 

 which is normal and typical in C. quadrntus, whilst the 

 rostrum is relatively little shorter than in that species (conf. 



