Mr. A. H. Cooke on Vulsella. 61 



characteristic red longitudinal lines to the greatest extent, and 

 is at the same time freest from those scaly foliations which so 

 often denote a cramped and distorted growth. Next comes 

 the form figured bj Delessert as the Laraarckian rugosa, in 

 which the beaks are prominent, the surface scaled, but there 

 is no manifest distortion ; the general shape may be compared 

 to that of a Septifer nicobaricus. Finally come the great mass 

 of the "species," the names given, mainly by Reeve, to the 

 inevitably varying shapes of the attached or confined shells, 

 of which spongiarum^ Lam., may be regarded as the type ; 

 ovala, Lam., representing the extreme of compression and 

 distortion. 



A detailed list of the " species " follows. 



1. Vulsella pholadi for mis, Reeve (Conch. Icon. vol. xi. 



Vulsella, pi. i. fig. 1). 



Hah. Ceylon {E. L. Layard). 



Type (the only specimen known) in Brit. Mus. 



Manifestly a debased and distorted shell, probably taken 

 from a crack or hole in a rock where it had not room to 

 expand. Sculpture, where any can be detected, the same as 

 in the form spongiarum, Lam. The " species " doubtless 

 belongs to that form. 



2. Vulsella isocardia, Reeve (Conch. Icon, ut sup. pi. i. 



fig. 2). 



TIab. Red Sea {Reeve), Suez^(/sse?, Malac. del Mar Rosso, 

 p. 100 ; MacAndreio, Ann. & Mag. Nat. Hist. 1870). 



Type in Brit. Mus. 



" The surface of this species," remarks Reeve, "■ is almost 

 wholly overlaid with a plaiting of finely pointed scales, the 

 umboes being convoluted inwards as in Isocardia.'''' It is to 

 be remarked, however, that the scaly surface of the shell is 

 more or less a characteristic of the whole genus, while the 

 position of the beaks, and the amount of curvature which they 

 describe, depend upon the compression to which the shell is 

 subjected in its various stages of growth. Belongs to the 

 form spongiarum, Lam. 



3. Vulsella tasmanica, Reeve (Conch. Icon, ut supra, pi. i. 



fig. 3). 



Hah. Tasmania [Reeve] Tenison-Woods, in Proc. Royal 

 Soc. Tasm. 13 Mar. 1877), S. Australia {id. ih.), Port Jack- 

 son {Angas, in P. Z. S. 1867, p. 930). 



Type in Brit. Mus. 



Shape inclining towaj-ds that of isocardia, i. e. more 



