l8o JOURNAL OF CONCHOI.OGY, VOI-. I3, NO. 6, APRU., I9II. 



it would appear that the mantle is closely and minutely tessellated, 

 instead of being covered with coarse tubercles ; he says nothing as 

 to sex. The shell is intermediate between the male and female 

 forms. The former, when viewed with the mouth towards the 

 observer, is the shape of a young Haliotis of the same size, whereas 

 the var. lain is broader and more boat-shaped ; while the shell of the 

 female (or type) is still more boat-shaped or convex, and the over- 

 lapping part of the shell is nmch broader. Again, with the shells 

 in the same positions, the whole interior of the spire is visible in 

 the male, in the lata form it is only partially so, while in the female 

 it is wholly concealed in the semi-tubular inner lip. The measure- 

 ments are : — 



Type form (female) length o'65in., breadth 0*450 (Jeffreys). 



Lata form - ,, o"35in., ,, 0*275 



Tentaculata form (male) ,, o"4oin., „ 0*275 



Now, it would be desirable to have the sexes of this species con- 

 firmed, as it appears to me that the var. lata is more likely to be the 

 male than Montagu's form tentaculata, for the following reasons : — 



(i) I find the var. lata nearly everywhere I find the type, instead 

 of in the single and isolated locality given by Jefireys. 



(2) I have rarely found a specimen of the var. tentaculata — three 



specimens from three different localities — though Jeffreys 

 says that " both sexes are found together." 



(3) The var. lata is uniform, and does not appear to possess a 



separate male and female form, analogous to the type, as 

 it should do to be consistent. 



It is important to observe that far from being a new variety from the 

 Shetlands, the lata form was known to Sowerby, who figures it well 

 in his " Index," with the exception tliat the spire should be depressed 

 instead of pointed. It was also known to Forbes and Hanley, who 

 figure it as var. tentaculata, with the following significant observation : 

 " Whether a still more depressed form, marked by Mr. Jeffreys as 

 Marsetiia coniplanata Leach, be distinct, is yet to be seen."^ Gwyn 

 Jeffreys, again, meant to figure the var. tentaculata, as he inscribes 

 on his plate the synonymous name coniplanata, but he actually 

 figures the var. lata. I do not know of any good figure of the true 

 tentaculata form. 



Gwyn Jeffreys may have been himself mistaken in saying that Mr. 

 Peach, "whose observations were continued regularly for ten years," 

 was mistaken in " supposing that his specimens belonged to the 

 species called tentaculata by Forbes and Hanley ; they are un- 

 doubtedly the typical form."'^ But they may very possibly have 



1 Brit. Moll., vol. iii., p. 359.. 



2 Brit. Conch., vol. iv., p. 23S. 



