394 MR. E. A. SMITH ON SHELLS FROM ADEN. [ JunC 1 6, 



to the British Museum by Mr. Mac Andrew, 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 S and M. cuming- 

 iana, Dunker, from Australia and the Red Sea ; the former " differing 

 chiefly [from marmorata] in being of a bro^vnish or rosy colour 

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

 dimensions and somewhat more coarsely sculptured tliau normal 

 specimens of marmorata. 



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

 (if. cuneata I am doulttful about), are quite recognizable and may 

 tlierefore 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 Ehzabeth by Sowerby, and from the Natal Coast by 

 Krauss (specimens from the latter locahty 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. 

 (^=macrophylla, Desh. &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. 

 {=hempriGhii, 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 o( the same anihor, respectively from the China Sea and 

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

 previously been considered synonymous with P. lithophaga by Tryon 

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

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

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



The MacAndrew specimens are exactly like the form bipartita. 

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



1 A specimen obtained by the * Challenger ' at Port Jackson more resembles 

 M. 'marmorata than M. canobita. 



2 Gould states that his species, like P. marmorata and P. ccxnohita, occurs 

 " imbedded in the test of a large Aseidian/' a fact of which Mr. Cooke seems to 

 have been unaware. 



