384 On the Willemoesia Group of Crwitacea. 



which I found to be full of the remains of the structures found 

 in the Glohigerina-ooze.y The statement that Alpheus bur- 

 rows in the mud is new to me. Its structure seems eminently- 

 unfitted for burrowing ; and I have watched the habits of 

 Alpheus megacheles (Hailstone), of which I have found large 

 numbers in rock-pools and among rocks in the Channel 

 Islands, but never a specimen burrowing in the sand. Again, 

 the whole structure of Willemoesia, compared with Scyllarus 

 and other Crustacea of kindred form, seems to suggest that it 

 is a swimmer and crawler, not a burrower ; and it will be ob- 

 vious to any one who knows what the bed of the Atlantic is 

 like, that there is no need that Willemoesia should burrow in 

 order to obtain possession of " structures found in the Olohi- 

 gerina-oozQ,y 



4. The relationship to Eryon. The connexion of Poly- 

 cheles with Eryon is very close. A glance at Dr. Wood- 

 ward's admirable restoration of the Liassic Eryon barrovensis, 

 M'Coy*, and a comparison of it with figures or specimens of 

 the smce-discoyered Poly cJteles, are sufficient to indicate the very- 

 near and most striking relationship. The only differences visi- 

 ble are the supposed presence of distinct eyes, and the absence 

 of a scale attached to the peduncle of the inner antennae ; add 

 to these the fact that Quenstedt thought that he had observed 

 palpi at the base of the gnathopods in Eryon, and we have the 

 sum of the apparent differences between the two genera. Dr. 

 Woodward has most kindly, in accordance with a request from 

 me, examined both fossils and drawings of Eryon on the above 

 points. In reply, I have received the following important 

 notes from that excellent fossil carcinologist : — 



" (1) I have not observed a palp at the base of the gnatho- 

 pods in Eryon'f. 



" (2) The inner antennae have no scale on the inner side ; 

 but the extremities of the raaxillipeds, which are round^ might 

 easily be mistaken for a scale. 



" (3) The eye in my restoration (of E. harrovensis) should 

 have been less pronounced, as, although I have little doubt of 

 its position, it has never been positively determined. I think 

 it can be seen on one side of Mr. Brodie's specimen, and on 

 both sides of Eryon (Coleia) antiquus, Brodp. sp. I cannot 

 see the eyes in Eryon crassichelis, H. Woodw." 



The only marked character, therefore, which is unques- 



* Woodward, Quart. Journ. Geol. Soc. vol. xxii. 1866, pi. xxv. fig. 1. 



t The organ which Quenstedt thought might be a palp of the gnatho- 

 pods was probably one of the 2nd or 3rd maxillipeds out of its place. 

 Both these in Polycheles are palpiform and might easily lead to the mis- 

 take. — A. M. N. 



