UROCOPTIS OF JAMAICA. 119 



3. U. INSTABILIS (Vendryes). PI. 34 a, figs. 9, 10. 



"Shell ovate-cylindrical, solid, rimate; color dark sanguin- 

 eous, not unlike that of some specimens of Cyl. sanguinea, 

 but the surface of instabilis exhibits in most specimens senii- 

 hydrophanous, more or less wide, transverse patches sparsely 

 and irregularly occurring, and apparently produced by some 

 indistinct lesions of the very thin epidermis ; spire describing 

 a well-drawn-out ovate outline; apex broadly truncate with 

 the loss of 6 to 7 of the earlier volutions, whorls remaining 

 7 to 8, almost entirely plain in some examples, or moderately 

 convex in others, subarcuately, obliquely and closely costulate 

 strise; the last whorl not detached in some examples, and de- 

 tached and produced in others, and generally more strongly 

 sculptured than the penult, and other whorls, with a well- 

 pronounced carina at the base ; suture lightly impressed and 

 submargined ; aperture slightly oblique, circular in some ex- 

 amples or transversely narrowed in others ; peristome slightly 

 tinged with the prevailing ground color of the shell, well 

 expanded all around and reflected, not continuous above, but 

 attenuated or reduced to a mere film and appressed to the 

 body whorl in some examples, or in others detached and con- 

 tinuous, and produced outward near the upper part of the 

 right side of the aperture and with a sinus or notch on the 

 produced part. Long., 24 to 25 mm. ; diam. at middle of 

 spire, 9 to 10 mm. ; aperture with peristome appressed, 8 mm. 

 high and wide ; when produced and with peristome detached, 

 fi mm. high, and 6 to 7 mm. wide." (Vendryes.} 



Jamaica: Phoenix Park, near the Monarque in the parish 

 of Saint Ann; environs of Brown's Town in the same parish. 

 (Vendryes.) 



Cylindrella (Thaumasia) instabilis VEND., Nautilus, xv, 

 p. 4, pi. 1, f. 9, 10 (May 1, 1901). 



"In several of its characters this species is rather incon- 

 sistent. In specimens found side by side and manifestly of 

 the same brood, some examples show strong affinities with 

 Thaumasia sanguinea, others with Thaumasia cylindrus, 

 others again with Gongylostoma lata (fThaumasia lata), in so 

 far that it becomes often very difficult to locate them deci- 



