350 A MANUAL OF AMERICAN LAND SHELLS. 



the oviduct. The vagina is moderately broad. The cloaca is short. 

 The exterior generative orifice is on the right side of the head, consid- 

 erably posterior to the tentacles. (See Terr. Moll. U. S., I, Plates 

 XIV, XVI.) 



Jaw absent. Lingual dentition as described above. There are 

 about 34-1-34 teeth in each row. I have shown in Fig. 375 the central 

 and various marginals from the first to the last tooth. The figures 

 show the teeth as seen from below, thus giving a perfect view of the 

 bases of attachment. The eighth tooth seems to be the largest, in an- 

 other the sixth. The central tooth I find great difficulty in studying. 

 It appears to have a loug, slender 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 marginals. 

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

 pointed median cutting point. (See the enlarged figure.) There are 

 no lateral teeth. The marginal teeth are all of purely aculeate type. i 



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

 and IV, Terr. Moll. The form from Key West, figured in Plate LXI, 

 Fig. 2, is a well-marked variety, but surely is not a variety of G. Tex- 

 asiana, as I formerly supposed it might be. After further opportuni- 

 ties of judging by the study of more numerous specimens. I am led to J 

 change my opinion as to the specific distinction of the form I formerly ' 

 called G. imvaUela. (See outline figure of Terr. Moll., III.) 



The rose-color of the living shell soon fades. 



Cirlaiidiiia. bullata, Gould. 



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

 Fio HTs. very light and thin, and so translucent as to show the 



whole of the pillar by transmitted light, very pale horn- 

 <;olor, tinged with rusty brown towards the aperture, 

 shining, and marked longitudinally with fine, rounded 

 striae; whorls 5, tumid, the last composing about seven- 

 eighths of the sliell ; suture delicate, not strongly im- 

 pressed ; a])erture two thirds the length of the shell, 

 narrow-lunate, 8ome\A hat dilated by the moderate arch- 

 ing of the i)illar inargin, the lower third of which takes 

 c.umdina huiiuta. the dircctjou of the axis; pillar margin covered by a 

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



