ihe Cyclostomacea of Eastern Asia. 4A7 
Viv. p. 16) * to be C. variegatus, Swains., and C. planorbulus, Lam., 
both from the Philippines. These shells possess a closely wound, 
thick operculum, membranaceous internally and subtestaceous 
without, very similar indeed to that of Opisthoporus, except that 
the latter is hollow within—a distinction the importance of 
which may be over-estimated. There is a deep sulcation round 
the margin, and considerable concavity externally. The shell is 
smooth or nearly so, very depressed, subdiscoidal, with a thick 
epidermis, and is generally precisely similar to the discoidal 
forms of Cyclophorus (e. g. C. stenostomus, Sow.), and especially 
to certain Burmese species (as C. calyx, Bens.), to which the 
Cycloti are doubtless very closely allied. The other Philippine 
species (C. mucronatus, Sow., C. pusillus, Sow., C. scalaris, Pfr., 
C. substriatus, Sow.) will be classed in the restricted genus, 
which doubtless comprises also the three Chinese species, as 
well as those of Cochin-China, Java, Borneo, &c., and several 
from the Moluccas, lately described by Dr. von Martens in the 
‘Malakoz. Blatter.? The nearest allies of the genus thus re- 
stricted being apparently amongst the species of Cyclophorus, 
Cyclotus must be referred to the same subfamily as that genus. 
IV. C. Macgillivrayi, Pfr., from the New Hebrides, may very 
possibly be a depressed form of the type for which Dr. Gould 
has proposed the generic name Ostodes. The operculum is 
subtestaceous, but otherwise in no respect different from that of 
some Cyclophori. C. daucinus, Pfr., and C. Recluzianus, Pfr., 
from the Solomon Islands, may be related ; but these species are 
only known to me by description. 
V. Omitting a few dubious species, there only remain the 
four Indian forms, and C. conoideus, Pfr., from the Seychelles 
and Mauritius, which very probably belongs to the same type as 
C. semistriatus. These species are nearly affined to Lithidion, 
but differ in their concentric operculum, and, being well distin- 
guished from all known genera, must be classed by themselves. 
[ propose to call them 
CycLoropsis, n. g. 
Testa late umbilicata, depressa v. turbinato-depressa, spiraliter 
lirata; apertura subcirculari. Operculum concentricum, multi- 
spirum, duplex, interne membranaceum, externe testaceum, margini- 
bus anfractuum externis elevatis. 
Animal Cyclostomatis, haud Cyclophori. 
Type, C. semistriatus, Sow. 
This genus will be classed as a subgenus of Cyclostoma by all 
who consider Otopoma and Lithidion as such. It may, as above 
suggested, be related to Aperostoma. In the raised margins of 
* J have not access to the original work at present. 
