1905.] NATURAL SCIENCES OF PHILADELPHIA. 213 



Family UROCOPTIDuE Pils. 



This family is represented in the Southwest by members of two very 

 distinct subfamihes: Eucalodiix>e with the genus Holospira, and 

 MiCROCERAMiN.E with thc genus Microceramus. 



Holospira is an old genus, containing several highly specialized phyla. 

 Our species fall into five groups as indicated below. The subgenera 

 were formerly defined by the internal lamellae alone ; but these are in 

 some cases of less significance than the general form and sculpture, 



A. — Last whorl distorted, its last half turning sinistrally. 



I. — Internal column rather large, smooth throughout; last whorl 

 sinuous, turning sinistrally. Aperture oblong, with a strong 

 fold within the right margin and a vertical columellar cal- 

 lous in the throat. Metastoma Strebel. One species, H. 

 roemeri. 



B. — Last half of the last whorl straightened, normal. 



II. — Internal column small, smooth and simple throughout, or 

 with a small axial lamella in the last whorl ; very slender 

 below, slightly wider above. Shell rather large, 19 to 29 

 mm. long, the individual whorls comparatively high; the 

 last one or tw^o more coarsely sculptured than the inter- 

 mediate ones. Number of whorls much less than the num- 

 ber of millimeters in the length of the shell. Haplocion 

 Pils. Species, H. pasonis Dall, H. hamiltoni Dall. 

 III. — Penultimate whorl with a short, stout lamella on the axis, 

 and a weaker one on the basal wall. Number of whorls 

 decidedly less than the number of millimeters in the shell's 

 length. Distomospira Dall. Species, H. bilamellata Dall. 

 IV. — Internal column moderate, one-fourth to one-sixth the diam- 

 eter of shell. Shell 9 to 18 mm. long in known species, com- 

 pactly coiled, ribbed or striated, the whorls short, their 

 number about equal to the number of millimeters in the 

 length of the shell, or exceeding that number. A short axial 

 lamella is present within the penult, whorl, and sometimes 

 short basal or parietal lamellae. Bostrichocentrum Strebel. 

 Type H. iryoni. 

 V. — Cavity of the penultimate whorl obstructed bj' four strong 

 lamellae, axial, basal, parietal and palatal. Holospira 

 s. sir. Species, H. goldfussi Mke. 



In addition to the species noticed below, the following species of 

 Holospira are known from north of the Mexican boundary: 



H. {Bostrichocentrum) pilsbryi Dall, rather doubtfully recorded from 

 New Mexico or Arizona, without definite locality, and known to inhabit 

 the Mexican state Puebla. 



H. {Distomospira) hilomellata Dall, from the top of Hacheta Grande 

 Mountain, Grant county, New Mexico. 



