14 PROCEEDINGS OF THE ACADEMY OF [1894. 



Morelet'm Gray, Pulm. Brit. Mus., p. 148. 1855. (Type H. eury- 



omphala Pfr. ). 

 Zoiiynliiia INIarteus, Mai. Bl. , 1865, p. 16. (Type H. bilineata 



P'fr. ). 

 Pafitlopsis Strebel & PfFeff'er, /. c. (Type P. carinatus Str.) 

 ZoniteSi s. g. Mesomphix Biuney, Terr. Moll., V, p. 98. 1878. 



The generic characters of this group are as follows: 



Shell rather large and solid but thin, umbilicated, smooth below, 

 lacking teeth or folds within; the lip simple and sharj). 



Foot double grooved above its margin, the grooves meeting above 

 the tail in a mucus pore; sole tripartite; dorsal surface from head to 

 mantle entirely lacking longitudinal grooves. 



Genital system lacking dart sac and (tther accessory glands. See 

 under 0. faUghiom, below. 



This genus contains the large Zonitoids of North America. It 

 has not been recognized as yet in Pakiearctic regions. 



0. fuliginosa fhiti". PI. 1, fig. 5. 



York Furnace, York County, Pa., 63,857. Collected by Wit- 

 mer Stone. No specimens were found by us in Maryland. 



The genital organs of this species and its allies seem to have been 

 misinterpreted by writers on United States forms, who have mis- 

 taken the swollen base of the vas deferens for the penis, and have 

 considered the penis itself to be a dart sack or prostate gland of some 

 sort. 



In 0. fuliginosa, the penis (P.), is a rather short stout sac, with 

 the retractor muscle (/■. p.) insei'ted at its apex, and attached dis- 

 tally to the floor of the lung. Internally the distal half of the 

 cavity of the penis is densely, finely and rather sharply granulated; 

 the opening of the vas deferens is near the apex of the cavity, and is 

 not provided with a papilla. The lower portion of the vas deferens 

 (v. d.) is enormously swollen; and for a short distance from its inser- 

 tion it is firmly bound to the penis itself. 



The vagina (vag.) is curiously swollen near the base. Thesperma- 

 theca (sp.) is large, subglobular, and together with its rather long 

 duct, is bound firmly to the oviduct. The albumen gland ((/. gl.) 

 is uncommonly large. 



The figure is drawn from a specimen collected by Mr. Witraer 

 Stone at York Furnace, York County, Pa. (No. 63,857). Several 



