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. 



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



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



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

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

 lot the rosea of Pfeiffer. In view of the error regarding the 

 [entity of rosea, Adams' brief notices of ambigua, magna, 

 ijor and fortis are quite inadequate for recognition, and 

 lone of the names would stand if the form had been elsewhere 

 >roperly defined. But Pfeiffer considered the whole series 

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

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

 >age, even though it was based upon a pathologic individual. 

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

 >urple color, the usually far weaker basal Jkeel, and the some- 

 rhat stronger shell; but all of these characters vary within 

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

 itween them. 



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

 typical small form described above, which is found 

 iroughout the areas 8, 8 a, 8 b of map 1, but is far more com- 

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

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

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

 >1. 28, figs. 16, 17). The shells from MandeviUe and those 

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



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

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

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

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

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



