206 On the Relations of Certain 



Succinea appendiculata , identical with jS. dej^ressa Eaiig, 

 is made by Fischer the type of a separate genus, Pellicida, 

 after an examination of the jaw, lingual dentition and gen- 

 erative organs; Albers (?. c.) adds that he had not yet 

 been able to decide upon the correctness of those views. 



From the subjoined diagnosis of the species received as 

 Succinea appendiculata from Guadeloupe, it will be seen that 

 the animal is limaciform, has a jaw, not as in 0. unguis, but 

 allied to that of genera and species of Ilelicinoe, and teeth 

 agreeing somewhat closely with those of Simpulojysis. In 

 pi. ix, we give figures of the animal (from an alcoholic spec- 

 imen), of part of the jaw and teeth (Figs. 2, 9, 10, 11). 



We now proceed to describe the jaw and lingual membrane 

 of 8uccinea appendiculata Pfr., received from Governor 

 Rawson : 



Jaw extremely thiu and transparent, long, low, slightly arcuate, ends 

 blunt, divided longitudinally by about 40 delicate ribs into as many 

 plate-like sections, of the character found in the jaws of Cylindrella, 

 Macroceramus and many species of Bulimuhcs. No appearance of trian- 

 gular upper median plates, however, as in Cylindrella, though the two 

 specimens examined by us are not perfect at that part. Both margins 

 serrated by the extremities of the ribs. The general character of these 

 ribs is the same as in Helix turhiniformis, figured by us in Ann. of Lye. 

 of Nat. Hist. N. Y. x, pi. 2, fig. 2. The jaw is quite membranous. 



Lingual membrane as usual in the HeUcinm proper (see Ann. Lye. Nat. 

 Hist. N. y. X, 163). Centrals subquadrate with a very large, stout, short, 

 pointed cusp, the side cusps obsolete. Laterals larger and more narrow 

 than the centrals, bicuspid, the inner cusp greatly produced, broad 

 and quite squarely terminating. The base of attachment of the laterals 

 is cut away on the inner side, leaving a large outer lateral expansion, 

 bringing to mind the much less developed one of Succinea. Marginal 

 teeth quadrate, gradually becoming modified from the laterals, the cusps 

 finally passing off into simple, obtuse papillae, the inner one the larger. 



The central and lateral teeth ai-e like those of Simpulopsis sulculosa as 

 flgui'ed by Ileynemaun in Malak. Blatt. xv, pi. 5, fig. 10, the central, 

 however, bearing a much more developed cusp in our species. The 

 marginals iu that figure, of the form found in Bulimuhis aurisleporis, 

 papyraceus, laticinctiis, etc., we failed to detect in our species. As already 

 stated, we found the marginals merely a modification of the laterals. 



The above description does not agree with that given by 

 Dr. Fischer (Melanges Conch., 69, t. vi, fig. 19) of Pellicula 



