HOLOSPIRA. 75 



The above description and figures 26, 27 are taken from 

 Strebel, who described and illustrated specimens bearing 

 Pfeiffer's label, C. Pilocerei, from the Pfeiffer-Dohrn collec- 

 tion. Figs. 23-25 are from Philippi, representing specimens 

 collected by Liebmann, as were those of Pf eiffer. 



It is a less slender shell than the original pilocerei, with a 

 shorter neck and less triangular aperture. 



H. tetrelasmus resembles H. tryoni externally, but is not so 

 smooth and the whorls are less narrow. 



Crosse has described a variety a little smaller than the type, 

 with 12 whorls, the last not detached. Length 11, diam. 4 

 mm. (pi. 21, figs. 28, 29). The internal characters of this 

 variety are not known. 



2. H. PILOCEREI (Pfeiffer). PL 22, figs. 45-48. 



Shell cylindrical, the apex conic, not truncate ; whitish ; lon- 

 gitudinally very delicately striate ; whorls 15, slightly convex, 

 the last rugulose, protracted, carinated above; aperture 

 spreading, pear-shaped. Length 7, diam. 1% lines [about 14, 

 31/3 mm.] (Pfr.). 



Cuautla de las Amilpas [in Puebla or Moreles], Mexico 

 (Hegewisch), on the cactus Pilocereus senilis. 



Cylindrella pilocerei PFR V Symbolae ad Hist. Heliceorum, 

 p. 47 (1841), and in PHILIPPI, Abbild. u. Beschreib, i, p. 183, 

 pi. 1, f. 7 (Dec., 1844). 



"I received for determination the single figured specimen 

 from the late Hegewisch, and the species is to be found in no 

 collection known to me. It is principally distinguished by the 

 blunt, conic apex, and by the horizontal free deviation of the 

 last whorl, which is carinated not at the base, but on the back. ' ' 

 (Pfr.) 



The original description and copies of Philippi 's figure of 

 the unique type specimen are given above. They indicate a 

 shell more slender than the il H. pilocerei" of later authors, 

 with the last whorl more produced and the aperture shaped 

 much as in H. goldfussi. The internal structure is unknown, 

 and no specimen other than the single original type is on 

 record. 



