NATURAL SCIENCES OF PHILADELPHIA. 247 



about its centre. In the other species examined, the retractor 

 muscle is inserted at the end of the penis sac. The same general 

 arrangement is found in the other species examined, bilineata (fig. 

 10), fusca (fig. 9), virginea (fig. 8), umbilicata (fig. 7), and in ab- 

 breviata, citrina, planilabrum, amanda. In P. virginea the con- 

 striction of the penis sac is much narrower and longer ; the upper 

 portion might be considered rather as a swelling of the vas 

 deferens. In most of the specimens examined there were well 

 formed shells of too full whorls in the oviduct, leading me to 

 believe the genus viviparous. Thus I found embryonic young 

 (usually only two) in planilabrum, abbreviata, umbilicata, bilineata, 

 amanda, and virginea. Those less grown were enveloped in a 

 sack. In gracilis, however, I found five white, calcareous eggs. 

 They contained, however, shells of two whorls, so that even if this 

 species actually lays the egg, it can only be at the moment the 

 young animal is ready to break it. In many of the undetermined 

 species, also, I found well formed eggs, and in some of them there 

 were these eggs, and also embryonic young not protected by eggs. 

 I suspect, therefore, that the young is actually brought forth living 

 in all cases. 



This closes my account of Partula. I add descriptions of 

 several species of Pulmonata, whose dentition has not yet been 

 published. As each lingual membrane is illustrated by a figure, I 

 have not considered it necessary to give a detailed description. 

 Macrocyclis euspira, Pfr. {Hyalina of von Martens, p 72.) 



Extracted from a dry specimen in the cabinet of Mr. Swift by 

 Mr. Thomas Bland. Ann. L. N. H. N. Y., XI. 73. 



. Jaw low,crescentic, ends pointed ; cutting margin with a decided, 

 sharp median projection. 



Lingual membrane long and narrow. Teeth arranged as in 

 Macrocyclis (see ante, p. 158). There are, however, no transition 

 teeth as in the American species, all the side teeth being true 

 marginals of the aculeate type. Teeth 30 1 30 (pi. XXI., fig. 3). 

 The centrals are deeply emarginate at the upper edge of their 

 base of attachment, and have expanded lower lateral angles ; they 

 have also a well-marked simple median cusp with a decided cutting 

 point. 



The species is placed by Yon Martens in Ammonoceras, a sub- 

 genus of Hyalina. 



