46 



lately Dr. Loveu stated that it was allied to Turbonella (Index Moli.. 

 Scand. 1 9). The examination of the teeth shows it to belong to the 

 typical Pleurohranchiata, and the form aud position of the gili its 

 affiuity with the geuera Pleurobranchus and JJmbrella ; indeed it 

 chiefly differs from the former genus iu having an extemal conic 

 patelloid shell, aud from the latter iii the head being produced and 

 the mouth uot sunkeu in a deep anterior pit. 



In the British Museum there are two species of this genus. 



1. T. punctulata, Rafin., T. Rajinesquii, Philippi, T. citrina, 

 Joanuis, Guerin, Mag. Zool. i. t. 36. 



Shell thin, whitish ; periostraca hard, opake, with dark brown 

 rays. Mediterranean. 



2. T. atlantica^Umbrella Mediterranea 1 MacAndrew, Ann. 

 Nat. Hist. 



Shell solid, bright yellow ; periostraca — ? N. Atlantic, Madeira. 



Fam. Umbrellad^. 



Umbrella mediterranea. 



The nucleus of this genus is very hke that oiTylodina, subglobose, 

 polished, sinistral, of one aud a half or almost two subcylindrical, ra- 

 pidly eulargiug whorls ; the adult shell is irregular iu the outline 

 and rather expanded on the hinder part of the right side, over the 

 gills ; the muscular scar is annular, coutinued, and of nearly uniform 

 breadth, but slightly iuterrupted in various parts. The chief dif- 

 ference between the shell of Ti/lodina and Umbrella is, that the shell 

 of the former is more elevated, very thin, covered with a hard, rather 

 paleaceous periostraca, aud the muscular scar is furnished with au 

 angular inflation on the hinder parts of the right side ; a sinistral 

 nucleus is fouud on several others ; shells as the geuera of Pyra- 

 midellidcB. 



Fam. Proserpinid^e. 

 Proserpina. 



Respiratory cavity open ; mantle free from the back of the ueck, 

 with a double edge, the outer one rather reflexed ; foot moderate,* 

 truucated iu front, acute, and keeled above behiud ; niuzzle short, 

 truucated, aunulated, with a triangular iuferior mouth ; teutacles 

 2, lateral, far apart, taperiug aud acute ; eyes moderate, sessile, at the 

 outer side of the base of the teutacles ; the front part of the back of 

 the foot coucave, surrounded by a continuation of the mautle, form- 

 ing a fleshy sub marginai fringe, which is fuller (when contracted in 

 spirits), crumpled and folded on itself on the left side. Operculum 



