MODIFICATION OF THE EYE PEDUNCf.ES IN CYilONOMUS. 451 



The drawing of a dorsal view of the complete C. quadra - 

 tus given iu fig. 1 of this plate shows a form which is closely 

 related to C. granulatus, Norm., but with well-marked, dis- 

 tinct specific character. A very astonishing feature, however, 

 is represented iu the figui-e, namely, the two posterior pairs 

 of thoracic limbs are pictured as being chelate, as in some 

 Dromiidte. This feature would necessitate the complete generic 

 separation of C. quadratus from C. granulatus; and as 

 this remarkable condition of the hinder thoracic limbs is not 

 mentioned in the text, and in the earlier description of the 

 genus by M. Milne-Edwards is expressly denied, I felt sure 

 that by a curious oversight the artist had figured the hinder 

 limbs of a Dromiid in place of those of the actual specimen 

 of Cymonomus which he had set out to draw. Such a con- 

 fusion of specimens by the artist, and the subsequent escape 

 of the ei'ror from detection by the zoologist for whom 

 the drawings have been made, is a possible psychological 

 phenomenon, and is comparable to a revoke in the game of 

 whist Avhen a card in the player's hand escapes his observation, 

 although he is looking at it, and knows that he must play 

 such a card if he have it. 



I accordingly wrote to my friend Professor Bouvier, the 

 distinguished naturalist in charge of the collections of Arthro- 

 poda in the Museum d'Histoire Naturelle of Paris, and he 

 has informed me that he is utterly astonished to find the 

 figure as it is, in spite of the fact that this and all the other 

 plates were carefully revised by him. He states that the 

 fourth and fifth thoracic pairs of limbs of C. quadratus 

 are not chelate, but resemble those of C. granulatus. At 

 the same time he was kind enough to send me some of the 

 type specimens of C. quadratus for examination, which show 

 the hinder limbs in place and of the usual form. He was also 

 so good as to send me specimens of C. granulatus from 

 the Mediterranean for comparison with Norman's types. 



We are now in a position to deal more definitely with Dr. 

 Norman's original specimens of C. granulatus. 



In the first place it is to be noted that M. Milne-Edwards 



