394 MR. E. A. SMITH ON SHELLS FROM ADEN. [JunC 16, 



to the British Museum by Mr. MacAndrew, certainly are like 

 M. marmorata, but more profusely ornamented with colour-markings 

 than the Mediterranean form. 



If we unite these two so-called species, we must also include 

 M. cuneata, Gould, from the Cape of Good Hope ', and 31. cumimj- 

 iana, Dunker, from Australia and the Red Sea ; the former *' differiua; 

 chiefly [from marmoraici] in being of a brownish or rosy colour 

 instead of pale green" (Gould) ^, and the latter being of larger 

 dimensions and somewhat more coarsely sculptured than normal 

 specimens of marmorata. 



However, I believe those forms, at all events three of them 

 (3/. cuneata I am doul)tful about), are quite recognizable and may 

 therefore be left separate. 



12. Arca lactea, Linn. 



This species ranges as far north as Great Britain ; it occurs in 

 the Mediterranean and along the West Coast of Africa ; it is recorded 

 from Port Elizabeth by Sowerby, and from the Natal Coast by 

 Krauss (specimens from the latter locality are in the British Museum) ; 

 and, finally, Mr. Cooke remarks that it " occurs in the Philippines 

 in a form precisely identical with that found at Suez." 



13. Venerupis irus, Linn. 

 (^^macropkyJta, Uesh. &c.) 



V. macrophylla and V. irus are certainly identical. The former 

 was originally described from the Philippine Islands, and has since 

 been quoted from the Persian Gulf (MacAndrew) and Aden 

 (Jousseaume, and Yerbury Coll.). 



14. Petricola lithophaga, Retzius. 

 { = hemprichii, Issel.) 



Doubtless Mr. Cooke is right in considering these two names 

 as belonging to one and the same species, and I fully admit the 

 correctness of his supposition that P. chinensis, Deshayes, and 

 P. bipartita of the same author, respectively from the China Sea and 

 the Philippine Islands, are merely slight variations also. They had 

 previously been considered synonymous with P. lithophaga by Tryon 

 (Amer. J. Conch, vii. p. 257), who also, rightly 1 think, includes 

 P. typica, Jonas, which has been recorded from South Africa by 

 Sowerby (Journ. of Conch, vol. vi. p. 157). 



The MacAndrew specimens are exHCtly like the form bipartita. 

 Jousseaume quotes this species, as P. hemprichi, from Aden. 



^ A specimen obtained by tbe ' Challenger' at Port Jackson more resembles 

 3/. viarmorata than M. ccenobita. 



^ Gould states that his species, like P. marmorata and P. coenoliia, occurs 

 " imbedded in the test of a large Ascidian," a fact of which Mr. Cooke seeuis to 

 have been unaware. 



