1890.] NEW-YORK MICROSCOPICAL SOCIETY. 3 



Pyrgula, Christofori and Jan, 1832. 

 Type, Melania helvetica^ Michelin, 1831. 

 = Pyrgtda anmdata, Christ. & Jan, 1832. 



Lingual dentition. The number of longitudinal rows of teeth 

 is seven, arranged 3-1-3, after the formula (i5-i8-ro)-i5 

 -(10-18-15). 



The rachidian tooth is longitudinally semi-elliptical, with the 

 sides nearly at right angles to the line of the base. Serrula 

 abruptly curving forward, and bearing about fifteen denticula- 

 tions. The central denticle is the largest and most prominent. 

 The lateral series diminish rapidly in descending order, so that 

 the denticles on the sides of the tooth are very small. 



Body of lateral tooth subquadrate, with an angular projection 

 at the basal margin, and a subovate thin alveolus in the central 

 portion. Peduncle slender. Serrula with ten denticles; the 

 fourth from the inner end of the series is much the largest. 



The first pleural has about eighteen denticles on the serrula. 

 The second is spoon-shaped, and bears about fifteen denticles. 



The shell from which the radula was obtained for this 

 description is from Italy. It was kindly furnished the writer 

 by Wm. H. Dall, Honorary Curator Department of Mollusks, 

 U. S. National Museum. 



