1898.] NATURAL SCIENCES OF PHILADELPHIA. 281 



Synopsis of subgenera. 



I. Axis slender, straight and simple. 



a. Macroceramus. Shell comparatively solid and large. Type 

 M. signatus Gldg. 



a'. Microceramus Pils. & Van., (n. s.-g.). Shell smaller, thin. 

 Type M. floridanus Pils. 



II. Axis with a strong spiral lamina. 



Spiroceramus Pils. & Van., (n. s.-g.). Dentition unknown. Type 

 M. amplus Gundl. 



Genus PINERIA Poey. 



This small group, originally described from the Isle of Pines, but 

 also occurring in several of the Caribbean Islands, is probably an 

 offshoot of the genus Macroceramus. The peculiar features of the 

 external anatomy described by Poey should be re-examined. 



Genus EPIROBIA Strebel & Pfeffer, 1880. 



Epirobia S. '& P., Beitrag zur Kenntniss der Fauna mexikanischer 

 Land- u. Siisswasser-Conchylien, Theil IV, pp. 77, 85. 



Type E. polygyra Pfr. PI. XVII, fig. 2 (dentition). For figure 

 of the axis, see Strebel, I. c, pi. 14, f. 14. 



Many-whorled, slender species of Eastern Mexico, usually retain- 

 ing the spire intact, differing from Urocoptis and BrachypodeUa in 

 dentition and in the hollow axis. Notwithstanding the entirely 

 " Cylindrella "-like aspect of the shell externally, these features un- 

 questionably locate the group near Holospira and Coelocentrum. 



Strebel and Pfeffer referred all of the Mexican Cylindrellas to 

 their group ; but it must be restricted by removal of the forms with 

 solid axis, which apparently belong to BrachypodeUa. In addition 

 to the two species mentioned below, E. berendti Pfr. [S P.] belongs 

 here, and probably gassiest Pfr. and swiftiana Crosse also. The " E. 

 morini Morelet," of Strebel & Pfeffer was incorrectly identified, and 

 probably a form of E. polygyra? The true C. morini is a Brachy- 

 podeUa with acutely keeled base. 



E. polygyra Pfr. [S P., P V.]. 



E. apiostoma Pfr. 



8 Since this paper was written, this form has been referred by Dr. von 

 Martens to C. polygyi'ella Mts. It is a true Epirobia. 



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