XXXVI NEOPETRJEUS. 



Group of B inscendens. Lower California. 

 B. xantusi W. G. B., xi, 148. B. cacotycus Mab., xi, 150. 

 B. digueti Mab., xi, 148. B. inscendens W. G. B., xi, 150. 



B. beldingi Coop., xi, 149. 



v. alta Dall, xi, 149. 



v. monticola Dall, xi, 150. 



Section Plicolumna Cooper, 1895. 



Vol. xi, p. 151. Slender and column-shaped. Distribution, 

 Lower California. 



B. artemisia W. G. B., xi, 152. B. abbreviatus Coop., xi, 153. 

 artemesia auct. B. ramentosus Coop., xi, 153. 



Section Sonorina Pilsbry, 1896. 



Leptobyrsus C. & F. not Leptobyrsa Stal. Columella bearing a 

 strong, callous lamella within the last whorl. Distribution, Lower 

 California. 

 B. rimatus Pfr., xi, 157. B. veseyianus Dall, xi, 160. 



bryanti Coop. B. lepido vagus Mab., xi, 161. 



B. spirifer Gabb, xi, 158. B. dentifer Mab., xi, 161. 



v. orthelasmus Pils., xi, 159. B. dismenicus Mab., xi, 162. 

 B. lamellifer Pils., xi, 160. B. subspirifer Mab., xi, 162. 



Genus NEOPETR..EUS Martens, 1885. 

 Manual, xi, p. 163 ; xiv, p. 152. Type N. millegranus Mart. 



This group is closely related to Drymceus, from which the shell 

 differs in having the vertical riblets of the nepionic shell wider spaced 

 and stronger than the spirals ; though both are sometimes obsolete, 

 leaving the apex smooth. 



The jaw is like that of DrymcEus, composed of 21 (lobbi, pi. 59, 

 fig. 1, after Binney) to 31 (altoperuvianus) delicate imbricating ribs, 

 which converge in the middle. The radula is broad, with numerous 

 teeth in each row (90.1.90 in N. lobbi, pi. 59, fig. 9, after Binney). 

 The centrals have a single long cusp ; the laterals bear a very long, 

 oblique, broad cusp, notched near the apex, the central and inner 

 cusps being concrescent. The marginal teeth in N. lobbi have a 

 large ectocone, and the united middle and inner cusps are shorter 

 thus resembling the laterals of Drymaeus, but in N. altoperuvianus 

 (pi. 59, fig. 4, after Binney) the marginal teeth are of the same 

 type as the laterals. The anatomy is otherwise unknown. 



Distribution, Andes of Peru. 



