Dr. J. E. Gray on the genus Proserpina. 188 



absent in Proserpina. But notwithstanding all these peculiarities, 

 I am inclined to arrange the family Proserpinidcs (including Proser- 

 pina and Ceres) in the order Scutibranchia, section Raphidoglossa, 

 and to form a suborder for it under the name oi Pseudobranchiay in 

 the same manner as the families CyclophoridcB and Helicinidce form 

 the suborder Phaneropneumona of the order Rostrifera. 



It may be thus characterized : — 



Pseudobranchia. Gills vascular, branched on the inner surface 

 of the mantle ; body and shell spiral ; eyes sessile ; operculum none. 



The open respiratory cavity, the separate sexes and the form 

 of the teeth, preclude its being arranged with the Pulmonobran- 

 chiata, with which it has been hitherto placed on account of its 

 terrestrial mode of life ; but as our knowledge of the structure of 

 MoUusca extends, it is found that some Pulmonobranchiafa are 

 marine, as Siphonariadce and AmphibolidcEy in the same manner as 

 the terrestrial CyclophoridcB and Oligyridce are properly arranged 

 with the marine and fluviatile Rostrifera. The Proserpinidce might 

 be arranged with the latter families, as was proposed before the 

 teeth were known ; but there can be little doubt that the animals 

 which have the very numerous rows of such peculiar-formed teeth 

 as the Raphidoglossa, must have very different habits and modes of 

 life from those which have only seven rows of nearly uniform teeth, 

 as the Tcenioglossa or Rostriferous Mollusca. 



And though the animal of the Proserpinidce differs from the 

 more typical Raphidoglossa, yet all the peculiarities, except the 

 vascular organs of respiration and terrestrial mode of hfe, are found 

 in some of the genera of the suborder. Thus the eyes of Fissurella 

 are sessile on the outer side of the base of the tentacle ; the whole 

 family of Neritinidce and some of the genera of Fissurellidce are 

 destitute of any lateral fringe or beards ; so that though these organs 

 are the usual characteristic of these animals, their absence is no 

 proof that the family does not belong to the group, especially when 

 we consider that the teeth have all the peculiarities, indeed, are per- 

 fectly typical in form with this well-marked and very peculiar tribe, 

 and very probably it may prove that many terrestrial Mollusca may 

 properly belong to the order. 



The lingual membrane elongate, broad, with numerous longi- 

 tudinal series of close-set teeth ; the central teeth in 1 1 longitudinal 

 series, 5. 1.5, the two outer teeth on each side being large and irre- 

 gular ; the lateral teeth are numerous, crowded, compressed, linear, 

 nearly equal, transparent, with recurved tip. 



In Ceres Salleana the lingual membrane is broad, elongate, with 

 close-set teeth. Teeth .00. 5. 1.5. 00, in numerous longitudinal 

 series ; the central tooth is oblong, with a smooth recurved tip, the 

 1st and 2nd lateral teeth rather broader than the central, with three- 

 toothed recurved tip, the 3rd narrow, elongate, with a slight recurved 

 end, the 4th and 5th much larger, oblong and irregular shaped, the 

 4th about half the width of the 5th, with 3 or 4 denticles on the 

 inner side of the upper edge ; the 5th very large, broad, with a 

 large subcentral reflexed lobe ; the lateral teeth are very numerous. 



