Dentition of Pulmonata. 38 



resenting the side cusps of the usual Helicince type) are nof present on 

 the first laterals, but are conspicuous on those farther removed, as shown 

 in figure b of the seventh lateral tooth. 



Orthalicus gallina-sultana, Chemn. 

 Maraiiou, Peru. Prof. Orton. 



An opportiiuit}'^ having been given me by the kindness of 

 my friend, Mr. Thomas Bland, of examining the animal of 

 Orthalicus gallina-sultana, Chemn., I here give descriptions 

 of its genital system and lingual dentition. It will be seen 

 that my figures of the latter do not agree with those published 

 by Troschel (Arch, fiir Nat., 1849, pi. iv, fig. 3), at least 

 so far as centrals and laterals are concerned, these teeth not 

 being represented in Troschel's plate. It must be borne in 

 mind, however, that at that early date, the membranes were 

 not so carefully studied as at present, and consequently the 

 peculiarity of these teeth may have been overlooked by 

 Troschel. Of the identity of the specimen examined by me, 

 there can be no doubt. 



The jaw (pi. IV, fig. E) is of the type usual in Orthalicus and Liguus, but 

 up to the present time never observed in any other genus. It is com- 

 posite, its separate plates being apparently soldered firmly at their upper 

 portions, where, indeed, they seem collectively to form a jaw in a single 

 piece as in Helix, etc., but at their lower portion positively detached and 

 free, imbricated one Upon another. The jaw may in one sense be said to 

 be in a single piece, as argued recently by Messrs. Fischer and Crosse, 

 (Moll. Mex. et Guat.), but with equal correctness it may surely be said 

 to be composite, as the amalgamation of the upper portion is produced 

 by the joining of absolutely separate pieces. There are fifteen of these 

 plates, the three upper central ones apparently lying upon the fourth, 

 which is very broad and extends from the upper to the lower margin of 

 the jaw. The jaw is strongly arched, with attenuated, blunt ends. There 

 are well marked perpendicular grooves upon the anterior surface of many 

 of the plates. 



The lingual membrane (pi. IV, tig. A-C) is very broad (13 mill.), for its 

 length (16 mill.). The rows of teeth are arranged in a backward curve 

 from the median line for a short distance, and then run obliquely to the 

 outer margin of the membrane. The central teeth have a long and rather 

 narrow base of attachment, squarely truncated at the top, incurved with 

 slight lateral expansions at the base. The reflected portion bears one 

 stout, median cusp, the side cusps being subobsolete. This cusp bears a 



