NATURAL SCIENCES OF PHILADELPHIA. 229 



also examined the jaw of 0. obductus, Shuttl. (Ann. Lye. N. H. 

 of N. Y., XL, p. 37.) All these species have the same composite 

 type of jaw. 



The lingual dentition of Orthalicus undatus is so nearly similar 

 to that of Liguus fasciatus, that I merely compare it with the 

 description given above of that species. In 0. undatus the cen- 

 tral tooth (pi. VI., fig. D) is broader in proportion to its length ; 

 the base of attachment is less expanded at the upper margin, and 

 very much less so at its lower margin, and the sides are not in- 

 curved ; the cusp is stouter, longer, reaching the lower edge of 

 the base of attachment, and it has subobsolete, but distinctly 

 marked side cusps ; the cutting edge is much more expanded, over- 

 lapping the next row of teeth. The first marginals differ from 

 those of L. fasciatus in having a less developed cutting edge, the 

 outer marginals have the side spurs to their cusps much more 

 developed and even the cutting edge is trilobed. The extreme 

 marginals are not so small. There are about 53 1 53 teeth, 

 on one part of one membrane; a wide part of another membrane 

 had 1061106. 



All the species of Orthalicus enumerated above whose dentition 

 is known have the same type of teeth as 0. undatus, excepting 0. 

 gallina-sultana. This last (see Ann. Lye. N. H. of N. Y., XL, 38, 

 pi. IV., fig. A) is peculiar in having a long, stout cutting point with 

 subobsolete side points to its central tooth, and three lateral teeth 

 of same form but unsymmetrical. Thus in both Liguus and Or- 

 thalicus we find the usual type of dentition is not constant except- 

 ing as to the marginal teeth. 



0. zebra. Too late for illustration I have received specimens 

 from Key West, collected by Mr. W. W. Calkins. It is the form 

 figured in Terr. Moll. U. S., IV., pi. LXXVIIL, fig. 12, and copied 

 in L. and Frw. Shells N. A., I., p.,216, fig. 370 (not fig. 371, which is 

 referred by Fischer and Crosse to 0. melanochilus, Val.). The 

 jaw has 7 1 7 separate pieces. The lingual membrane has 

 126 1 126 teeth. The teeth are of same type as in 0. undatus, 

 but the cutting edge of the centrals and first laterals is shorter 

 than the base of attachment. It is, perhaps, a variety of undatus. 



Genus PUNCTUM, Morse. 



But one species of this genus has been described, P. pygmseum, 

 Dr., hitherto known in America as Helix minutissima, Lea. A 



