NO. 1483. 



VROCOPTID MOLLUSKS—BARTSCH. 



135 



Thi.s species was made the type of the section ILtjylosfeiinna by 

 Doctor Dall, which is characterized as havinga short, stout, axial himella 

 only. There was one specimen in the collection which had the outer 

 wall on one side removed to expose the pillar; the removal of the wall 

 seems to have carried away a small portion of the septum, separating the 

 last whorl from the penultimate, and this unfortunately happened to 

 be just the place upon which the short (poorly developed) basal fold 

 is situated. 



Jlaplostemma., therefore, nmst l)e considered a sjmonym of Disto- 

 m,ospira. The basal fold extends over about one-fifth of a turn on the 

 floor of the penultimate whorl. 



HOLOSPIRA (BOSTRICHOCENTRUM) TRYONI Pfeiffer. 



There is one specimen of this species. Cat. No. 107325 U.S.N.M., 

 in the collection which comes from Salle, and was collected at the type 

 locality, Matamoras de Izucar, Puebla, Mexico. The specimen has 

 15 whorls and measures: Length, 12.5 mm.; diameter of tenth whorl, 

 4.4 mm. ; diameter of penultimate whorl, 3.8 mm. 



HOLOSPIRA (BOSTRICHOCENTRUM) PILSBRYI Dall. 



There are two lots of this species in the collection, one specimen. 

 Cat. No. 21762 U.S.N.M., labeled Mexico, without specific data, the 

 other, ('at. No. 56932, U.S.N.M., containing 120 specimens, was col- 

 lected about the sulphur springs around the city of Puebla, Puebla, 

 Mexico, by the Mexican Geographic Commission. The following- 

 table gives measurements of 20 specimens from the last lot containing 

 the type: 



Measurements of Holospira {Bostrichocentrum) pllshryi. 



a Type. 



