GLYPTOSTOMA. 373 



their terminal complications. I have not figured them, being uncertain whether 

 they shouUl be considered as a part of the genital system. They may be the 

 same as figured on PI. XV. Fig. Q, or the individual furnishing the genitalia 

 there figured may thus show the near relation oi fucla and rujlcincta. 



GLYPTOSTOMA.^ 



Animal as in Pntula. 



Shell widely umbilicated, depressed, with wrinkle-like striae, solid; whorls 

 6, the last depressed-globose, not falling at the aperture ; aperture oblique, 

 subcircular; peristome simple, acute, thickened within, its extremities ap- 

 proached, that of the columellar short, scarcely reflected." 



Inhabits the Californian Region at San Diego. 



One species only is thus far known, Newherryanum. Its jaw is low, wide, 



slightly arcuate, ends but little attenuated, 

 Fig- 257. , , . . . 1 . 



blunt ; cutting margin without median pro- 

 jection ; anterior surface with numerous 

 (about 16), stout, separated ribs, deeply 

 denticulating either margin. 

 , ^ -- . Lingual membrane (PI. X. Fig. A) 



Jaw of G. Newherryanum. ° v o y 



long and narrow. Teeth 47 — 1 — 47, with 

 17 perfect laterals. Centrals with the base of attachment long and nar- 

 row, with greatly expanded lower, lateral angles, the upper margin rounded, 

 broadly reflected ; reflection large, stout, with obsolete side cusps, but with 

 decided, triangular side cutting points ; median cusp very stout, short, with a 

 long, acute cutting point reaching beyond the lower edge of the base of attach- 

 ment. Laterals like the centrals, but asymmetrical by the suppression of 

 inner, lower, lateral angle of the base of attachment and inner side cutting 

 point. The transition from laterals to marginals is marked by the lesser pro- 

 portional development of the cusp and greater development of the cutting 

 point. Marginals low, wide, the reflection equalling the base of attachment 

 and bearing one inner, short, stout, oblique, blunt cutting point, and one outer, 

 shorter, blunt cutting point. 



This species, like all others, has great variation in the development of the 

 cutting points on different parts of the same membrane. 



1 The name is suggested by the sculptured parietal wall of the aperture in young speci- 

 mens of the only species known, q. v. 



2 Testa late umbilicata, depressa, ruguloso-striata, solida, anfractus 6, ultimus 

 depresso-glohosus, antice non descendens ; apertura obliqua, subcircularis ; peristoma 

 simplex, acutum, intus iucrassatum, marginibus approximatis, columellari brevi, vix 

 reflexiusculo. 



Maxilla arcuata, costis validis distantibus (circa 16) exarata; margines valdo dentati. 

 Lamina lingualis ut in Helice videtur ; dentes marginales subquadrati. 



