394 



PROCEEDINGS OF THE ACADEMY OF 



[June,. 



body, it has a basal sheath, and a slender, conspicuously annul ated 

 papilla, one-third the length of the penis or longer. The flagellum is 

 well developed for Sonorella. The penial retractor is inserted at the 

 apex of penis and base of epiphallus. The vas deferens is slender 

 throughout. Measurements of the organs in mm. follow. 



Specimens from Station 11, and numerous others from Station 5, 

 opened but not measured, were sufficiently examined to show that 

 the specific characters — great length of penis and vagina— are con- 

 stant. 



S. santaritana differs from other species of the same range by its 

 wider umbilicus, the more approaching ends of the lip, and especially 

 by the great length of penis and vagina. In the characters of the 

 genitalia it is nearest to S. rinconensis P. and F. (these Proceedings 

 for 1909, PI. XXII, fig. 5). That species differs by having a still 

 longer vagina, and a more capacious shell with larger aperture and 

 relatively smaller umbilicus. S. dalli and *S'. virilis are somewhat 

 related, but differ in characters of both genitalia and shell. 



This is the most abundant and widely distributed Sonorella of 

 the part of the Santa Rita Range which we explored. 



In size, specimens from Walnut Canyon (PI. IX, figs. 1-26) measured 

 from 19 to 25.8 mm. diameter, but only in one colony were such 

 small ones found, the minimum size in other colonies is about 21.5 

 mm. 



In Stations 10, 11 and 14 they run from 20.4 to 22.5 mm. In 

 other stations the size is about typical. 



A beautiful albino (PI. IX, fig. 3) was taken at Station 5. It shows 

 very faint traces of the shoulder band and the embryonic shell is 

 faintly buff, but otherwise it is pure white. Genitalia as in .the 

 colored form. 

 Sonorella walkeri n. sp. PI. IX, fig'i. 1, 4a, -16 



The shell is umbilicate (the width of umbilicus contained about 

 9 times in the diameter of the shell), rather solid, pale cinnamon, 



