204 SYSTEMATIC ARRANGEMENT 



broad angular sinus on the hinder part of the right side. Mouth 

 like Pleurobranchus. Lingual membrane broad. Teeth in many 

 longitudinal series, forming angular cross lines. Gill pinnate, like 

 Pleurobranchus. The animal and shell evidently intermediate be- 

 tween Pleurobranchidce and Umbrelladce. 



Fam. X. UMBRELLADiE. 



Body suborbicular. Head not produced. Tentacles two, slit on 

 the outer side. Mouth sunk in the groove, with a retractile pro- 

 boscis. Teeth in numerous longitudinal series, similar. The foot 

 large, thick, including the viscera, deeply notched in front. Mantle 

 enclosed. Shell external, conical, calcareous. Muscular scar ring- 

 like, submarginal. 



1. Umbrella. 



1. U. umbellata, t. 163. f. 1, 2, 4, t. 165. 



2. U. Mediterranea, t. 163. f. 3, t. 164. 



Lingual membrane of Umbrella Mediterranea broad, longitu- 

 dinally plaited. Teeth in numerous oblique cross lines, each con- 

 taining very many small, closely pressed, compressed, sharp-edged, 

 transparent teeth. 



Foot of Umbrella Mediterranea very large, thick, including the 

 viscera, flat beneath, scarcely elevated above, deeply notched in front, 

 and externally covered with large, irregular, rounded tubercles. The 

 mantle small, enclosed under the shell, finely toothed on the edge. 

 Gill on the right side, continued behind nearly to the left side, formed 

 of many compressed, elongate, pinnatifid leaves connected at the base. 

 Vent prominent, behind the end of the gill. Tentacles two, placed 

 above the fissure of the foot, contractile, oblong, linear, longitudinally 

 slit externally. Eyes small, on the inner side of their base. The 

 orifices of generation in the anterior fissure, below the tentacles, 

 surrounded with some lips ; and, below the opening of the mouth, 

 furnished with many lips, the outer of which is called, by Blainville 

 and Delia Chiaje, the "buccal tentacles." — Philippi s Moll. Sicil. t. 7. 

 f. 11,11«. 



De Blainville erroneously describes the organs of two sexes in the 

 same individual, the oviduct in the front part of the right side, with 

 a short groove to the root of the male organ, which is at the base of 

 the hinder right tentacle. 



§§ Teeth in three (or sevenl) longitudinal series. Body elongate, 

 covered with a mantle. Tentacles nonel (p. 201). 



Fam. XI. RUNCINAD.E. 



Body elongate, lanceolate. Mantle distinct. Gizzard testaceous. 



