Willemoesia Group of Crustacea. 383 



slight diversity in the lateral and dorsal spiny adornments of 

 the carapace *. These are the only two specimens I have 

 seen ; my conclusion that their difterence is sexual may be 

 wrong. Can Mr. Bate prove it to be so f ? 



2. The eyes. Eyes are things to see with. Has Poly- 

 cheles such organs ? Mr. Spence Bate objects to my friend 

 Prof. Heller saying that the eyes are rudimentary : have 

 lenses then been found? There will not be space in the 

 ' Annals ' of November to go into this matter, nor have I time 

 to do so. It will suffice to say, that it were to be wished 

 that Mr. Bate had lettered the figures of the plate to have 

 made them more clear; I confess to difficulty in understanding 

 the drawings. The organ he describes is clearly not the same 

 as that which Heller speaks of when he writes, " Distinct 

 eyes are not present, but on the bases of the peduncle of the 

 inner antennse one observes on both sides a small round black 

 spot as an indication of an organ of sight." 



3. Is Polychehs nearly related to Alplieus"^ I cannot find 

 the slightest sign of such relationship. The mouth-organs, 

 those important elements in the classification of the Crustacea, 

 are wholly different ; but the mandible of Polychehs is not 

 unlike that of Astacus, with which genus Polychehs was 

 compared by Heller. Mr. Bate mentions two points of resem- 

 blance to Aljyheus : 1st, that the embryos of both have " large 

 and distinctly pedunculated eyes," a character which, I take 

 it, is not very rare among the embryos of the Macrurous 

 Crustacea ! 2nd, Alpheus is spoken of as in " its adult condi- 

 tion burrowing in the mud of the sea-bottom," and Wille- 

 moesia, " I believe, burrows in the soft mud of the deep-sea 

 bottom. This is borne out by the contents of the stomach, 



* Had Willemoes-Suhm been acquainted with the genus Polycheles, he 

 would never have established the genus Willemoesia. No doubt Heller's 

 work was not in the ' Challenger ' library ; but there must have been the 

 ' Porcupine ' Report of 1870 ; and had he looked there he would have 

 found that I had recorded Polycheles typhlops as taken off the Spanish 

 coast (Station 9), the name of which is peculiarly suggestive. Mr. Bate 

 seems also to have overlooked the circumstance that Polycheles typhlops 

 had been found in the Atlantic, as he only gives the Mediterranean as 

 its habitat. 



+ There is another case, however, in which ]Mr. Bate persists against 

 proof in maintaining a genus founded on mere sexual characters. In the 

 'Annals' of May he describes (vol. v. p. 411) a Lestriyonns s^miidorsalis ; 

 but all other carcinologists are, I believe, a:;reed that Lestrigonus is 

 simply the male of Hyperia; and I have myself paired the British species 

 described by Bate and Westwood (see Brit. -Assoc. Report, 1868, p. 286). 

 I may add that the second crustacean described in the May number 

 {Dinstylis himargi7iatics, Bate) is my Diastylis spinosa (Brit.-Assoc. Report, 

 1868, p. 271), as will be obvious to any one comparing the descrip- 

 tions. 



