54 PARARHYTIDA-THYSANOPHORA. 



last one wide, rounded at the periphery. Lip generally somewhat 

 retracted at the upper insertion, thickened on the baso-columellar 

 margins, dilated at the basal insertion. Surface smo.oth or rib-striate 

 above. Type H. saisseti Montr., pi. 7, figs. 22, 23, 24. 



The soft anatomy is unknown. Binney has figured the jaw and 

 teeth of P. astur. The jaw is low, wide, slightly arcuate, ends hardly 

 attenuated, blunt; anterior surface without ribs; having a wide, 

 blunt median projection ; a line of reinforcement runs parallel to 

 the cutting edge; upper margin with a strong muscular attachment 

 (pi. 8, fig. 7). The radula has 21-9-1-9-21 teeth. Centrals tri- 

 cuspid ; laterals lacking the entocone, at least on the inner teeth ; 

 marginals tricuspid, the entocone and mesocone united. 



It will be seen that this differs from typical Pararhytida in the 

 median projection of the jaw and the loss of entocones on the lateral 

 teeth (pi. 8, fig. 8). 



As no type was designated by Ancey, I have considered H. sais- 

 seti Montr, as such, for I suppose this was Bayle's intention. 



Species. 



P. baladensis Souv. i, 116. P. occlusa Gass. i, 122. 



P. oriunda Gass. i, 121. P. astur Souv. i, 117. 



P. bruniana Gass. i, 119. P. saisseti Montr, i, 117. 



P. perroquiniana Cr. P. goulardiana Cr. i, 122. 

 P. turneri Pfr. i, 119. 



Genus THYSANOPHORA Strebel & Pfeffer, 1880. 



Thysanophora S. & P., Beitr. Mex. Land- und Siisswasser- 

 Conchylien, iv, p. 30 (proposed for impura, paleosa, conspurcatella). 

 -PILSBRY, Proc. Acad. Nat. Sci. Phila. 1889, p. 192. 



Microphysa MARTENS in Albers, Die Hel., p. 82 ; type Helix 

 boothiana Pfr. Not Microphysa Westw., 1834 (Hemiptera), nor of 

 Guen. 1841 (Lepidoptera). 



Acanthinula STREBEL & PFEFFER, 1. c., p. 31, and of v. MAR- 

 TENS, Biol. Centr. Amer., p. 130. Not Acanthinula Beck. Ptyclio- 

 patula PILSBRY, Proc. Acad. Nat. Sci. Phila. Sept. 17, 1889, p. 191 ; 

 Nautilus iii, p. 62 (proposed for cccca, dioxcoricola, punctum, plagio- 

 ptycha, etc.). 



Eudada\. MARTENS, Jahrb. D. M. Ges. 1877, p. 347 (for H. 

 tnusicola Sh.)- CROS^E, Journ. de Conchy 1. 1892, p. 14. Not 



