MELVILL AND STANDEN : GENtJS SCALA IN THE TERSIAN GULF. 351 



A few fragments also occurred in the dredging at 156 fathoms, of 

 three hitherto unknown Scalce. One of these, when full grown, must 

 be a very fine species, intermediate between Cirsotrema and Acrilla, 

 of the form of A. acuminata Sowb., but interstitially decussatcly- 

 striolate. Another is near S. thelcteria, a third akin to S. kieneri 

 Tapp.-Can. We can only hope to receive examples fit for description 

 before long. Enough, however, has come to hand to shew how 

 favoured are the Persian Gulf and Gulf of Oman as regards this very 

 beautiful genus. 



♦ ■•«♦ 



NOTE ON MACRON TROCHLEA. 



By EDGAR A. SMITH, I.S.O. 



(Read before the Society, September 9, 1903.) 



In the last number o{ \}m?, Journal^ p. 326, Mr. J. Cosmo Melvill has 

 given a list of the species belonging to the genus Macron. The first he 

 refers to under the name oi M. kellettii of A. Adams, overlooking the 

 fact that this species had fourteen years previously been desc4-ibed by 

 Gray as Pollia trochlea. 



P. P. Carpenter referred to the latter, but was under the impression 

 that it was a manuscript name. 



The synonymy therefore will stand thus: — 



Macron trochlea (Gray). 

 Pallia trochlea Gray, Zool. Beechey's Voyage, p. in, (1839). 

 Piisio trochlea Gray, MS. in Brit. Mus. ; P. P. Carpenter, Moll. 

 Western North America, p. 140, Rep. Brit. 

 Ass., 1863, p. 534. 

 Pseudoliva kellettii K. Adams, Proc. Zool. Soc, 1853, p. 185. 



No reference is made by Mr. Melvill respectijig the relationship of 

 A/. cEthiops (Reeve) to the present species and he does not seem to be 

 aware that this subject has been discussed by R. E. C. Stearns.^ The 

 latter had a fine series of specimens given to him which demonstrated 

 that "the grooving is an uncertam character." The number of 

 specimens before him was "fortunately ample enough to settle all 

 doubts and prove that the two forms should be united under one 

 specific name." Mr. G. B. Sowerby who has very great experience 

 in the variability of shells informs me that he is of the same opinion. 



The type of trochlea in Gray's collection, now in the British 

 Museum, is intermediate in respect of the spiral grooving between 

 typical cethiops and kellettii., the types of which are also in the 

 Museum. 



I Proc, Acad. Nat. Set. Philadelphia, 1878, vol. 30, p. 397. 



