THE NATURAL HISTORY SURVEY. 171 



Superfamily Agnathomorpha. 



Mouth provided with jaw; radula with aculeate teeth; 

 mouth frequently developing finger-like appendages; cerebral 

 ganglia concentrated, in close contact. 



FAMILY CIRCINARIIDyE. 



"Foot-edges with no. trace of pedal grooves; no tail gland; 

 sole undivided. Side teeth unicuspid, thorn shaped, with nar- 

 row basal-plates. Shell with simple lip and without opaque 

 markings."* 



GENUS CIRCINARIA (Bsck, 1837). Pilsbry. 



Macrocyclis Beck, of Authors. 



Selenites Fischer, 1878 (nou Hope). Haplotrema Anc. 



"Shell: Thin, widely umbilicated, depressed, striate or 

 wrinkled, color uniform; whorls 4^-5, the last broad, de- 

 pressed, moderately deflexed in front; aperture obliquely 

 ovate; peristome somewhat thickened or expanded, the mar- 

 gins approximating, the basal shortly reflexed." 



"Animal: Heliciform; mantle posterior, covered with a 

 shell; eye-peduncles long, slender; foot narrow, twice as long 

 as the diameter of the shell, tail pointed, scarcely reaching 

 behind the shell; respiratory and anal orifices on the right ot 

 the mantle, under the peristome of the shell; generative orifice 

 behind the right eye-peduncle; no distinct locomotive disk or 

 caudal mucus pore. Carnivorous." 



"Jaw: Crescentic, ends sharply pointed, anterior surface 

 striated; cutting margin smooth, with a median projection."** 



Radula: With numerous rows of teeth arranged en chev- 

 ron. For detail of the radula see concavus. 



"Genitalia: The epididymis is extremely long and very 

 large, forming the peculiar feature of the system. The geni- 

 tal bladder is oval, with a long duct, which is very much broader 

 at the end nearer the vagina. The penis sac is long, gradually 

 tapering at its apex, where it receives the vas deferens. Upon 

 the side of the vagina, about the middle of its length, is a wart- 

 like protuberance, which may be a dart-sac or a vaginal pros- 

 tate."** 



Distribution: North America. 



"Pilsbry, Guide to Helices, p. XXVIII. 



**\V. G. Binney, Man. Amer. Land Shells, pp. 79 and 83. 



