186 CERION, GROUP II. 



Caymans, in being rather solitary, at best only a dozen or so being 

 found together, consequently they were not abundant. At the time 

 of my visit, the last week in April, the weather was mainly dry, and 

 they were clinging to the low, stunted plants, or to rocks, and not 

 feeding." (Maynard.} 



As usual in Cerion, the sculpture, color and size vary within wide 

 limits, and there is complete intergradation of the forms, although 

 a typical form prevails in any given local colony. The following 

 have been named : 



a. Ribs irregularly and widely spaced on the last 3 whorls. 



b. Large and stout, about 28x13 mill., whitish, pannosum. 



Variegated, 31x11 m\\\.,fuscum. 

 b l . Smaller, about 22x10 mill., whitish, intermedium. 

 a 1 . Ribs regular or nearly so, 21-27 on penult, whorl. 



b. Ribs 22-27; shell whitish, about 23x10 mill., copia. 



b l . Ribs 25-27 ; white with purple-brown intervals ; 24x10 



mill., lineotum. 



5 2 . Ribs 21-23; shell whitish, 1 5-17x7 J mill., parvum. 

 o 2 . Ribs subobsolete on the later whorls. 



b. Shell whitish, about 22^x10 mill.; cone rather acute, 



perplexum. 



b 1 . Shell whitish, about 16x7-| mill., glaber. 



Color-form fuscum Mayn. (pi. 27, figs. 7, 8, 9). A form of C. 

 pannosum has been called Strophia fusca by Mr. Maynard. It is 

 dull purple with the riblets mainly white, fading to light reddish- 

 brown above. Length 26^, diam. 12 mill. Maynard's type meas- 

 ured 31.2x11.2 mill.; and he gives the variation as from 33.7x13.7 

 to 22.5x10.5 mm. As in pannosum, the riblets are rather wide- 

 spaced. It occurred " on the west end of Little Cayman, low down 

 in the thick scrub. They are quite solitary in habit, and rather 

 rare." Figs. 7, 8 are copied from Maynard. 



Form intermedium Maynard. (PI. 27, figs. 10, 11, 12.) 

 Smaller than C. pannosum, but similar in the white or bluish-white 

 color with few darker flecks above, or none, and in the rather wide- 

 spaced, often irregular costation, there being about 17-19 ribs on the 

 penult, whorl. The aperture is either dark in the throat, or through- 

 out, the lip in the latter case being brown-tinted. Peristome usually 

 thickened less than in pannosum. Length 21.5, diam. 10 mill.; 

 length 24, diam. 11.3 mill.; the types 22.5x10, and 22x10 mill. 



