86 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



base of attachment, truncated and emarginate above and below, with slightly 

 expanded lateral angles. The sides are somewhat incurved, giving the tooth 

 the appearance of a simple modification of the base of attachment of the mar- 

 ginals. There is a single median cusp with obsolete side cusps, and a long 

 pointed median cutting point. (See the enlarged figure.) There are no lat- 

 eral teeth. The marginal teeth are all of purely aculeate type. 



The shell is a very variable one, as shown by the figures in Vols. III. and 

 IV. The form from Key West, figured in PI. LXI. Fig. 2, is a well-marked 

 variety, but surely is not a variety of G. Texasiana, as I formerly supposed it 

 might be. After further opportunities of judging by the study of more numer- 

 ous specimens, I am led to change my opinion as to the specific distinction of 

 the form I formerly called G. parallela. (See outline figure of PI. LXII.) 



The rose-color of the living shell soon fades. 



Glandina decussata, Desha yes. 

 Vol. III. PI. LXI. Fig. 1. 



Shell oblong-conic, thin, shining, horn-color ; whorls 7 to 8, longitudinally 

 striate, and covered with numerous minute revolving lines ; suture slightly 

 crenulated ; aperture oblong, half as long as the shell ; columella curved, trun- 

 cated, covered with light callus. Length, 50 mill. ; diameter, 18 mill. 



Achatina decussata, Deshayes in Fer. Hist. 182, PL CXXIII. Fig. 34 ; LI. 



CXXIV. Figs. 33-35 (1850). (Vide Pfeiffer, Mon., IV. 644). 

 Glandina truncata, var., Binney, T. M., II. 302, PI. LXI. Fig. 1. 

 Glandina comeola, W. G. Binney, Proc. Phila. Acad. 1857, 189 ; T. M., IV. 139. 

 Glandina decussata, Tryon, Am. Journ. Conch., II. 227(1866). — W. G. Binney, 



L. & Fr.-W. Sh., I. 18 (1869). —Fischer and Crosse, Moll. Mex., 112 (1870). 

 Olcacina comeola, Pfeiffer, Mai. Blatt. 1859, 51. 



A Mexican and Guatemalan species, also found in the Texas Region at 

 Devil's River and on the banks of the Nueces River. It is very rare in collec- 

 tions. 



Animal, dentition, and genitalia unknown. 



Glandina bullata, Gould. 

 Vol. III. PI. LXII. a. 



Shell elongate ovate, ventricose, widest a little behind the middle, very light 

 and thin, and so translucent as to show the whole of the pillar by transmitted 

 light, very pale horn-color, tinged with rusty brown towards the aperture, shin- 

 ing, and marked longitudinally with fine rounded striae ; whorls 5, tumid, 

 the last composing about seven eighths of the shell ; suture delicate, not 

 strongly impressed ; aperture two thirds the length of the shell, narrow-lunate, 

 somewhat dilated by the moderate arching of the pillar margin, the lower 

 third of which takes the direction of the axis ; pillar margin covered by a 

 delicate lamina of white callus. Length of axis, 37 mill. ; breadth, 20 mill. 



