76 THE NAUTILUS. 



Length 3.2, height 2.3, diameter 1.5 inches. 



Shell of medium thickness, thinner behind. Teeth double in left 

 valve, single in right. Laterals rather thin, nearly straight. Car- 

 dinals stumpy. Muscle scars well marked ; generally separate, some- 

 times confluent. Pallial line distinct in front, less so behind. Cavity 

 of shell dish-like ; of the beaks deep and full. 



Sometimes the dorsal muscle scars are situated in the extreme end 

 of the beak cavity, but generally upon the base of cardinal and dor- 

 sal plate. Nacre rose-color, with blotches of yellow surrounded by 

 brown. Cavity nearly always studded with numerous pearly excres- 

 cences. 



Flesh of animal whitish or salmon-colored exteriorly, but shows 

 scarlet when cut. Eggs carried in all four gills, very red, and the 

 gravid animal thus presents a striking appearance. 



Habitat : Lanana and Banita Creeks, near Nacogdoches, Texas. 

 About 200 specimens were taken on July 10, 1901, by Messrs. Askew, 

 Strode and Frierson. 



Examples may be seen in their cabinets, and in the U. S. National 

 Museum and Academy of Natural Sciences, where the types are 

 deposited. 



Q. lananensis is closely allied to Q. askewii Marsh, both by its con- 

 chological and anatomical characteristics. It may be differentiated 

 from that shell by being longer, more compressed, more oblique, and 

 its shell is never so inflated and thickened in front as Askewii, and 

 not so acutely angled on the posterior ridge. 



Internally, lananensis is rose-colored nearly invariably, and the 

 color is uniformly spread over its surface. Askewii is mostly white, 

 and when colored (pink), the color is almost always confined exterior 

 to the pallial line. 



Finally, Q. Askewii never possesses those peculiar pearly excre- 

 scences which seem to belong to lananensis. This species was col- 

 lected many years ago at the type locality by Mr. H. G. Askew. But 

 that gentlemen's innate modesty forbade his describing the shell, and 

 he generously gave to me this honor. 



Lananensis is the shell quoted as having been found by Mr. Askew 

 in the Lanana Creek, in the " Contributions to the Natural History 

 of Texas" (page 321), by Mr. J. A. Singley, and called by him U. 

 cerinus Conrad. Its relationship to this abundant Louisiana shell is 

 so remote, however, that it is not worth while to point out their dif- 

 ferences. 



