UROCOPTIS, S. G. GONGYLOSTOMA. 263 



Group of U. wrighti. 



Long and very slender, fusiform shells, the diam. contained 

 5 to 9 times in the length; narrowly truncate, variegated 

 white and corneous, the last whorl free and descending in a 

 long neck (except in U. contentiosa, which probably is not 

 closely related to the other species). Axis with a single, 

 more or less spinose spiral thread. Central and eastern Cuba. 



The dentition of U. wrighti (pi. 61, fig. 12) is notable for 

 the rapid decrease of the teeth in size towards the edges. The 

 decrease is gradual and the teeth normal in form, formula 

 9.1.9. In U. baculum (pi. 60, fig. 11) the radula is narrower, 

 7.1.7, or rather 5.2.1.2.5, the two inner laterals on each side 

 being distinctly larger than the third, as in the west Cuban 

 group Tetrentodon. 



I. Last whorl adnate; suture subcrenulate ; length 14 to 16, 

 diam. 3 mm., with 14-15 whorls. U. contentiosa, no. 151. 

 II. Last whorl descending in a rather long neck. 



1. Whitish with sparse corneous' streaks; oblique 

 thread-like riblets separated by spaces 2 or 3 times 

 their width ; neck rather long; 12 to 14 x 2 mm., with 

 13y 2 to 15 whorls. U. hilleri, no. 146. 



2. Brownish-corneous with white or corneous, oblique, 

 more widely spaced riblets ; neck long ; 16.3 to 20 x 

 2 to 2.2 mm., with 15y 2 to 20 whorls. 



U. wrighti, no. 147. 



3. Creamy or pink, with sparse dark-corneous lunate 

 streaks; rather weak wide-spaced arcuate riblets; 

 neck long; 11.7 to 14x1.7-1.9 mm., whorls 14 to 17. 



U. baculum, no. 148. 



4. Diaphanous, whitish, obliquely ribbed ; 15 to 17 x 

 2.5 mm., whorls 15 to 17. U. lajoncherei, no. 150. 



5. Brownish-corneous, glossy, closely striate near the 

 sutures, smoother in the middle of each whorl ; length 

 11.7 to 17, diam. 2.2 to 3 mm., with 11 to 13 whorls. 



U. producta, no. 149. 



146. U. HILLERI (Pfeiffer). PI. 59, figs. 77, 78. 



Shell very slender, fusiform, widest in the middle, slowly 



