644 LOWKU CALIFOKNIAN BULIMUI.UB DALL. 



<'()iii|t;ir('il with t1i;il of the othci' species, as iiiimht be expected troni its 

 sniaUcr ranuc in area and altitude. The iiillar bears an observable 

 lold, but no hiniiua. 



Bulimulus (Leptobyrsus) Zeledoni Dull, sp. nuv. 



Costa Rica, Zeledon, iMus. Keg. 98231. (Plate Lxxi, Fi<;-. 2.) 

 Sliell thin, colorless, with translucent, polished, pale yellow epidermis 

 and se\en wliorls; apical pit small, the nuclear whorls rounded, the 

 ribl(^ts upon them close set and cut by ecjuidistant spiral gi-ooviny;-, so 

 as to produce a close, even reticulation like that of close-woven cloth; 

 apex rather pointed, whorls slightly rounded, suture distinct; surface 

 sculptured with obscure increnuMital wrinkles and very faint sparse 

 spiral stria;; last whorl more than half the lenj^th of the whole shell; 

 base rounded, with a narrow umbilicus, over which the i)illar lip is 

 broadly retlected; ai)erture short, Avide, peristome thin, retlected, except 

 near the sutural commissure, the retiec;tion becoming- more nuirked in 

 l)roportion as one passes from the suture forward, and widest of all at 

 the i)illar, which is strai,i»ht, almost forming an angle with the lij) at its 

 base; body with a slight wasli of callus; a sliglit fold at the back of the 

 pillar, but no lamina. Jjongitudeof shell oO, of last whorl 17, of aper- 

 ture 11 ; maximum latitude of shell 13.5, of aperture 10 nun. 



I have included this species, collected by Sen or Don Jos('' Zeledon, 

 because it does not seem to be described, and also because it seemed 

 naturally associated with the species of Lower California, to which this 

 article is devoted. It is easily recognized wIumi perfect by its nuclear 

 sculpture and simple coloration, polished ei)i(lermis, and ratiier wide 

 squarish aperture. 



vSiibsoctioii 1?. witli a prominent laniiua projecting from the ])illar in tin' lirsl lialfof 



the last whorl. 



Tliis gron[) at present com))rises three si)ecies, and t!ie internal fea- 

 tures are essentially the same in each. About tlu^ time that the ikmuiI- 

 timate whorl is beginning to be fornuHl the ])illar becomes gyratory, so 

 that, viewed from below, it descril)es a spiral curve around an inuigi- 

 nary cylindrical axis of greater or less diameter. After completing its 

 round and beginning on the last whorl the outer edge of the gj^e be- 

 comes thickened and «'xp:inded in a tin-like manner with thick rounded 

 margin; the twist of the pillar becomes more nearly axial, and at the 

 aperture of the shell sliows merely as a fold or rounded ridge such as 

 api>ears in the various species of subsection A. 



Bulimulus (Leptobyrsus) spirifer (JaUU. 



"In the mountains, among rocks, from San Antonio beh)w La Paz to 

 near San Uorja, an«l in the highest mountains, perhaps even farther 

 north." (labb. San Jose on the Gulf of California. lielding. (Tlate 

 LXXii, Fig. 8.) 



Nearly all the si»ecimens in the national collection were received from 

 Clabb, so that they are authentic. The species has been confounded 



i 



