~'l DUYM.l.rs, MKXICO AM) CKNTHAI. AMKHK'A. 



"This fine species is distinguished by its iliin pure white shell, 

 \\ith not very numerous round brown spots; these arc arranged on 

 the last whorl in four spiral rows, on the preceding whorl in three, in 

 the one before that in two rows, those of the second row being often 

 a little larger than the others. The spots are placed rather distant 

 one from the other, and they can also be regarded a- being arranged 

 in vertical rows, forming interrupted stripes from the suture towards 

 the umbilicus, but this arrangement is not so regular as the spiral 

 one. The spiral stria? of the shell are exceedingly fine. The aper- 

 ture is pure white, the peristome very slightly reflected. 



"The average length of the shell is 28-30 mill.; but one figured 

 by Strebel (fig. 12) attains even 34^ mill., and one reported by Herr 

 Hcige, from Mexico, the locality of which is not especially stated, is 

 only 24 mill. long. The breadth of the shell is equal to the length 

 of the aperture and to about half the length of the whole shell." 

 (Martens. ) 



The only species closely allied to this is D. dormant, but in that 

 the spire is more conic. The name tolonacus is derived from the 

 name of the tribe of the Totonacs, that dwell in the district of Mis- 

 antla. 



D. DOMINICUS Reeve. (See p. 3.) 



Callejon de la Zatnora, near Vera Cruz (Strebel); Mirador nnd 

 Tulxiscn (Ilerendt); C///H/HIS ( ( ihieslircght); Lalma, Y/trn/nn (Htil- 

 prin Exped.); San Nicolas, central Nicaniynu (Tate). 



D. ALHOSTKIATI-.S (Strebel). PI. 12, figs. 25, 26. 



In most respects so similar to /). ifii/inir/is that only its differen- 

 tial characters need be >tated. The shell is only slightly shining, 

 light horn-color, and has separated, rather wide. whiti>h growth- 

 streaks shading out on both sides. Apex brownish horn-color; be- 

 tween the 2d and Ith whorls three narrow dark brown bands appear, 

 nio-tly interrupted and crossed by brown longitudinal streak-, form- 

 ing an irregular markinir quite .-imilar to that of J>. keterogeneut. 

 The sculpture does not differ, and of the structure and form of the 

 whorls it is only to be said that the basal half of the last whorl is 

 sometimes darker colored. There is on the inner margin of the peri- 

 stome a rather- strongly thickened whitish streak, showing the whit- 



