PUPILLIDAE AND RELATED GROUPS. 195 



Columellar retractor (left) gives off almost immediately 

 the shortly united left free and buccal muscles, soon after 

 the right free retractor and then continues to form the strong 

 tail fan. Eight free gives off right ocular, which passes 

 through penioviducal angle, at about level of salivary glands, 

 and divides terminally into fan of short muscles, of which first 

 is inferior tentacular, second goes to vagina and penioviducal 

 angle and remainder to sides of foot. 



Cerebral commissure about % as long as width of each 

 cerebral ganglion ; pleural connective medium in length ; pedal 

 much longer. Salivary glands long lanceolate, about length 

 of buccal mass but more slender; right one % to ^ longer 

 than left and completely separate from it; ducts short. 

 Oesophagus long and slender (probably knotted when con- 

 tracted). Stomach without special gland, but alongside in- 

 ferior lobe of liver which is narrow and terminally bilobed 

 like in Vallonia (Steenberg, 1917) although intestinal S-loops 

 are mainly imbedded in albumen gland. Radular formula 

 (fig. 6):14 — 1— (6 + 8), with 83 rows (T). 



Strobilops texasiana Pils. & Ferr. Plate 26, fig. 4. 



Cf. S. lahyrinthica Hanna (1922, Naut. 25: 91) and this 

 vol., p. 13. 



The animal described was collected June 18, 1929, along the 

 Guadalupe River, north of New Braunfels ; the other 23 indi- 

 viduals in the lot lacked terminal male genitalia. All indi- 

 viduals in several lots of the related S. lahyrinthica, from 

 several localities, are similarly emasculate. Only salient dif- 

 ferences from the structure of S. aenea will be noted. 



Carrefour (fig. 4) enlarged tranversely at apex. Vagina 

 relatively shorter. Epiphallus nearer penis. Penial appen- 

 dix long clavate (base much contracted). Penial retractor 

 bifurcating near origin from diaphragm ; insertion on appen- 

 dicular penial arm farther from apex. 



Valloniinae. 



Details of the anatomy of Vallonia (oviparous) are given by 

 Steenberg (1917), whose figure of the genitalia in V. costata 



