C Y C L T U S . 



Plate I. 



Genus CICLOTUS, Guildaig. 



Jeista plus ndmm depresse ttirbiiiala vel discoidea, sippissiint: 

 late tivihilicata, CDifi'actiljiis sithaiirjudis, ajKrtnru par- 

 viiiscuUi, inaryiiiibiis coutbiuis vel callo siiiiialo juiictis. 

 Operculum- orbiculare, teslaceuiu, arctispimm, exlns 

 coucaviuaculum, aiifractuuiii inargbw in laminam iu- 

 curvam interdum elevotu. 



Shell more or less depressly liirbiiiated, or discoid, mostly 

 broadly uuibilicated, whorls rather narrow, aperture 

 rather small, margins continuous, or joined by a sinu- 

 ated callosity. Operculum orbicular, testaceous, closely 

 spired, rather concave outwartily, edge of the whoi'ls 

 sometimes raised into an incurved lamina. 



In this division of the Laniarckian genus Cijclostoinn 

 there are two well-marked groups, each niunbering about 

 a dozen species. The species of the first of these, the 

 laigi'st and most conspicuously coloured, are natives of 

 the woods of New Granada, West Columbia, Bolivia and 

 Brazil. The shell is elegantly convoluted in a very dis- 

 coid manner, largely openly undjilicated, and enveloped 

 «ith a very characteristic epideruiisof a rich burnt-brown, 

 banded with olive-green colour. The species of the second 

 group are natives of Jamaica, of rather smaller size and 

 stouter grov\th, chiefly of a rose-brown hue, more or less 

 plicately wrinkled. Half-a-dozen species from India and 

 China, and the same number from the rhilip])ine Islands, 

 together with four i'rom Xew Guinea, two from ]!ombny, 

 and one from the Lao Mountains, have been referred to 

 Ci/ctotn.i, but they are uuich sujaller tlian the Cijcloli of 

 the Western Hemisphere, and of quite a different typical 

 character. \\ e have a small species of Ci/dotus from 

 Mauritius, and one also from Xatal. 



The last whorl of this species is not excavately angled 

 and ridged around the undjilieus as in its nearest ally 



C. JllVUlictHfiis. 



Species 2. (Fig. a, b, Mus. C'nuiing.) 



Cyclotus seminudus. Cijd. testa anijulat'iM excavato- 

 umhilicalu, subdepressu , fulcd , ruseo-brnuneo splraliter 

 latifasciatii, avfractibus uiidique ruijutla, riiijis pariirii 

 obsoletis. 



The seminude Cyclotus. Shell augidarly excavately 

 undjilicated, slightly depressed, fulvous, encircled 

 uith a broad rose-bi'own band, whorls everywhere 

 wrinkled, wrinkles partially obsolete. 



Ci/clostuina seiuiiiudum, C. B. Adams, Contr. Conch. No. 

 viii. p. 143. 

 Cyclotus Jamaicensis, var., Bfeifl'er. 



llab. Jamaica. 



Dr. Pfeifl'er formerly considered this a distinct species 

 from C. Juii/aici'imifi. 



Species 1. (Tig. a, b, Mus. Cuming.) 



Cyclotus ciiANULArus. Cj/cl. testa vwdice umbilkatd, 

 depresse orbiculari, fulvd, roseo-bruuneo spirallter 

 latifasciatd, anfractibus subaiigiistis, supen/e depressis, 

 undiqne corrugatu-g ranatls . 



The gkanclated Cyclotus. SIk'II moderately undjili- 

 cated, depressly orbicular, fulvous, spirally broadly 

 banded with rose-brown, uhorls rather narrow, de- 

 pressed at the upper part, everyu here wrinkle-grained. 



Chitty, i[S. in Mus. Cuming. 



Hub. Jamaica. 



Species 3. (^lus. Cuming.) 



Cy'clotus gigaxteus. Cycl. testa ampliter aperte mu- 

 bilicatd, depressu, solidiuseuld, ustulalo-fusco olivacec- 

 viridi lute fusciutd et tiiictd, ad pcripJieriuvi fascia 

 amjustd fulvd cingulutu, avfractibus augnstis, ad su- 

 turas plai/o-iuipiressis, supra conctiitrice Jilv-striatis, 

 iifra corrugato-striatis. 



The gigantic Cyclotus. Shell largely openly nmbili- 

 cated, depressed, rather solid, burnt-brown, broadly 

 banded and stained with olive-green, encircled with 

 a narrow fulvous band at the periphery, whorls nar- 

 row, flatly impressed at the sutures, concentrically 

 thread-striated above, wiinkie-striated below. 



Cijclostouia gigauteum, Sowerby, Pro. Zool. Soc. 1S43, 

 p. :30. 

 Ci/clutus giganleus, Gray. 



llab. Panama (in the neighbouring woods). 



This fine species should be regarded as the tyjie of the 

 "■enus. 



December, 18(53. 



