CYCLOSTOMA. 
Piate VI. 
Species 28. (Mus. Cuming.) 
CycLosToMA LiRatuM. Cyel. testé patente perspective 
umbilicatd, depress, subdiscoided, livido-fuscescente, 
anfractibus angustis, ad suturas impressis, deinde ro- 
tundatis, liris tenuibus acutis equidistantibus undique 
cingulatis ; aperturd parvd, labro dilatato-fimbriato, 
rufescente. 
THE RIDGED CycLostoma. Shell openly perspectively 
umbilicated, depressed, nearly discoid, hvid-brown, 
whorls narrow, impressed at the sutures, then rounded, 
encircled throughout with thin sharp equidistant 
ridges; aperture small, lip dilately frilled, reddish. 
PreIrrer, Pro. Zool. Soc. 1852, p. 64. 
Hab. ? 
Closely allied to C. Deshayesianum, and doubtless from 
the same locality. The spiral ridges which characterize it 
are remarkable for their extremely delicate thread-like 
aspect. 
Species 29. (Fig. a, 0, Mus. Cuming.) 
CycLosTtoMa ARTICcULATUM. Cycl. testé profundé umbi- 
licaté, depressé orbiculari, solidiusculd, violascente- 
alba, teniis violaceo-articulatis hic illic cingulatd, 
anfractibus spiraliter densé obtuse liratis et carinatis ; 
apertura parviusculd, labro parum reflexo. 
THE ARTICULATED CycLostoma. Shell deeply umbi- 
licated, depressly orbicular, rather solid, violet-white, 
encircled here and there with violet-articulated fillets, 
whorls spirally densely obtusely ridged and keeled ; 
aperture rather small, lip but little reflected. 
Gray, in Griffith’s Cuv. Anim. King. pl. 28. f. 1. 
Cyclostoma filosum, Sowerby. 
Cyclostoma Terverianum, Grateloup. 
Hab. Rodriguez. 
Of rather solid growth, tinged and filleted throughout 
with pale violet. Mr. Woodward gives an interesting ac- 
count of some living specimens of this species, collected 
in 1858 by Madame Ida Pfeiffer in Rodriguez, to which 
island it is believed to be peculiar. Numerous examples 
were conveyed to the Mauritius, where they continued ac- 
tive, but took no food during two months. ‘‘ Three indi- 
viduals,” continues Mr. Woodward (Pro. Zool. Soc. 1859, 
p- 204), “remained alive after the voyage to England, 
which occupied ten weeks, and several others were suffi- 
ciently preserved for examination. They were brought 
over packed in paper and rags, in a tin pot with a lid, and 
were not taken out till a fortnight after their arrival. One 
of these snails lived for some months under a bell-glass, 
with moss and ferns, and afforded frequent opportunities 
for examination. The animal was of a pale buff colour, 
with darker tentacles and muzzle ; the tentacles were acute, 
rugose, and slightly annulated, the muzzle anuulated, 
grooved beneath, and bilobed at the end, which was con- 
stantly used in walking. The foot was ample, with a deep 
central groove dividing it into two lateral elements, moved 
alternately in walking. 
When it retired and closed its 
shell, it still adhered, and sometimes became suspended 
by a tenacious thread of mucus.” 
Species 30. (Fig. a, 6, Mus. de Burgh.) 
CycLostoma Ds-Bureuim. Cycl. testd patentissime ex- 
cavato-umbilicaté, plano-orbiculari, fumeo-yrised, ma- 
culis parvis fulvis et albis ad carinas et suturas arti- 
culatd, spird depressissimda, anfractibus undique decussa- 
tim striatis, superne declivi-planis, deinde acute remote 
tricarinatis, carind mediand multo prominentiore ; 
apertura subcirculari, fauce purpureo-fuscd, labro cal- 
loso-reflexo, intense sanguineo. 
De Buren’s Cyciostoma. Shell very openly excavately 
umbilicated, flatly orbicular, smoky-grey, articulated 
at the keels and sutures with small fulvous and white 
spots ; spire very depressed, whorls everywhere decus- 
sately striated, slopingly flattened at the upper part, 
then sharply distantly three-keeled, the middle keel 
being much the more prominent; aperture nearly 
| circular, interior purple-brown, lip callously reflected, 
| deep blood-colour. 
Hab. Madagascar. 
| This very beautiful species, from the collection of Mrs. 
| de Burgh, was procured in Madagascar by the renowned 
_ traveller, Madame Ida Pfeiffer. It comes very near to C. 
formosum in the details of sculpture and colour, but the 
spire is flatly immersed, and the upper of the two encireling 
keels is almost obsolete. The lip is of an unusually deep 
blood-red colour. Mrs. de Burgh possesses two speci- 
mens exactly alike in these particulars. 
November, 1861. 
