UROCOPTIS OF JAMAICA. 135 



erally. C. rosea v. fortis C. B. A., HENDERSON, Nautilus, viii, 

 p. 19, no. 95. C. rosea var. fortis C. B. A., Contrib. no. 9, p. 

 161 (1851). 



The following references to "C. rosea" probably pertain to 

 the present species : Amer. Journ. Conch., iv, p. 186 ; v, p. 37 

 (jaw figd.) ; Ann. N. Y. Acad. Sci., iii, p. 125; Journ. de 

 Conch., 1870, pp. 9, 12, 25 (teeth) ; Proc. Acad. Nat. Sci. 

 Phila., 1873, p. 248 ; Beitr. Mex. Land- u. Susswasser- Conch., 

 iv, p. 106, pi. 13, f. 6, 7 (teeth). 



The name C. ambigua was originally given to a single ab- 

 normal specimen of the form known to Adams as C. rosea, but 

 not the rosea of Pfeiffer. In view of the error regarding the 

 identity of rosea, Adams' brief notices of ambigua, magna, 

 major and fortis are quite inadequate for recognition, and 

 none of the names would stand if the form had been elsewhere 

 properly denned. But Pfeiffer considered the whole series 

 to be mere varieties of C. cylindrus; and in the absence of a 

 competing name, it seems best to adopt the first one on Adams ' 

 page, even though it was based upon a pathologic individual. 



U. ambigua differs from U. cylindrus in the rose instead of 

 purple color, the usually far weaker basal keel, and the some- 

 what stronger shell; but all of these characters vary within 

 wide limits, so that there is no sharp line of demarcation 

 between them. 



Mr. Jarvis distinguishes three races of U. ambigua: (1) 

 the typical small form described above, which is found 

 throughout the areas 8, 8 a, 8 6 of map 1, but is far more com- 

 mon in Manchester, area 8. This form measures from 18 to 

 26 mm. long, and varies from a dull brown tint, scarcely per- 

 ceptibly rosy (Mandeville, fig. 30), to a bright rose (Pratville, 

 pi. 28, figs. 16, 17). The shells from Mandeville and those 

 from Williamsfield, in Manchester (pi. 29, figs. 28, 29), are 

 typical. 



A form apparently referable to typical U. ambigua (pi. 29, 

 fig. 27) occurs at Great Valley Estate, Hanover (C. B. Tay- 

 lor), in the area of U. zonata. The shells are a beautiful rose 

 color. About 14 or 15 whorls are deciduous, the first 2i/ 

 being smooth. The earlier whorls are either pale or black. 



