Naticse, Lamellarise, and Velutinse. 57 



the position of the heart I thuik both leaves are branchial. The 

 oesophagus is extremely short ; it almost immediately opens into 

 a large oval stomach that is always filled with pulp. The oeso- 

 phageal cordon consists of two oval yellow ganglia on each side, 

 and one smaller a little posterior to the others. The verge is 

 yellow, not long, and is a miniature of that organ in Murex un- 

 datus, except that it is rather more pointed, and has the orifice 

 at the point instead of a little below it as in that species. 



This animal inhabits, at Exmouth, the deepest waters of the 

 coralline zone. This is the last genus which in respect of the 

 shell and animal cannot be placed in a simple natural series, but 

 must fall therein by a branch ; it is not so aberrant as Lamellaria, 

 as here the coriaceous mantle has vanished, and the auriform 

 shell protecting the viscera and branchise has become external ; 

 nevertheless, by its thick epidermal coat it appears to supply the 

 place of the thick external mantle of Laminaria. Its place in 

 the natural order is conspicuously marked out by the retractile 

 proboscis as a sequence to the last genus, and it is assigned to 

 the present family as a striking point of transition to the Cana- 

 lifera. 



Velutina flexilis, Montagu. 



This is a Scottish and Hebridean species : it appears to belong 

 to this genus. For some account of the animal I refer to the 

 ' British MoUusca/ vol. iii. p. 350. 



The Velutina otis of authors, now Otina otis, has been depo- 

 sited in this genus, but from observations published in one of 

 my papers, I believe its relations are in the neighbourhood of the 

 Bullce and Conovuli ; at the same time I admit that it requires 

 further examination. 



I now conclude, and if it be considered, ' Et genus insolitum 

 concordi lege coegit,' or in other words, that I have applied a 

 law, that of union, to a strange or anomalous race, and brought 

 its members more prominently into view, the design of this 

 paper will not have entirely failed. 



I am. Gentlemen, your most obedient servant, 



William Clark. 



P.S. — I have just received from Mr. Damon, of Weymouth, 

 some minute shells collected in Zetland ; I have met with them 

 occasionally on the South Devon coast. They are partly dwarf, 

 or an immature variety of that singularly variable species the 

 Rissoa inconspicua, and are marked in the direction of the axis 

 with about seven brownish red lines that are tolerably regular 

 and equidistant. 



I believe they are the long-lost species of Adams, "lineis 



