12 LAND AND FRESHWATER 
cuspid laterals, the points being blunt and rounded. The jaw (fig. 6) 
is semicircular in form, particularly well rounded on the side of the 
muscular attachment, while on the cutting-edge it is very convex, 
and with a well rounded central prominent projection. 
The odontophore of this subgenus is therefore in every respect 
similar to that of Macrochlamys, Benson*; and the jaw, though more 
bent, is also of the same type. 
This subgenus, therefore, I consider ranks very close to Macro- 
chlamys, and must be placed at present next it. Whether its cha- 
racters are sufficient to retain it, is a question that must be settled 
hereafter, when all these different genera are more closely examined. 
The shell (fig. 1) is of a solid texture, and the solid or very sinuate 
form of the columellar margin (fig. 2) is a distinct departure from the 
oblique and feebly-reflected columellar margin of Macrochlamys. 
I hope to be able to examine before long some more spirit- 
specimens. 
1. Microcysrina Rinku, Morch. (Plate III. fig. 1.) 
Microcystina rinkii, Morch, Journ. Conch. Oct. 1872, p. 311; id. 
Oct. 1876, p. 356; Nevill, Hand-list, p. 39. no. 171. 
Locality. Island of Teressa, one of the Nicobars. 
Shell closely umbilicate, subglobosely conoid, polished above ; 
sculpture, very fine, regular disposed, and parallel longitudinal striz, 
26=-01 inch (fig. 1a); colour rich sienna above, below covered 
with a dull white deposit ; spire subconoid, sides flat, apex blunt ; 
suture shallow; whorls 5, the last well rounded ; aperture oblique, 
symmetrically lunate, the body-whorl covered with a distinct callus ; 
peristome thin, columellar margin (fig. 2) oblique, much thickened, 
reflected and very sinuate, the reflected portion ending abruptly at 
right angles to the base of the last whorl. 
Size: major diam. 0°21 inch., alt. axis 0°10 inch. 
- 54 mm., 35 | 2G im. 
For the animal of this species I am indebted to Mr. G. Nevill, to 
whom I owe many thanks for this and other rarities. 
Original description (J. c. p. 811) :—** 7. anguste umbilicata, con- 
vevo-depressa, tenuis, polita, nitidissima, brunnea, umbilicum versus 
pallidior ; strie incrementi obsoletissimee, remotissime ; spira parum 
elevata, obtuse convexa ; sutura obsolete appresso-marginata ; anfr. 4, 
vie convexi, angusti, ultimus subdepresso-rotundatus ; apertura obli- 
qua, lunata, margine columellari (vel labro) dilatato, reflexo, profunde 
sinuato, fere emarginato, umbilicum propendente. 
“ Diam. maj. fere 5 mill., axis 23 mill. 
‘‘ Hab. Sambelong, bords de la rivicre Galathea: trois exem- 
plaires. 
“ Obs. Nanina (Microcystis) mitiuscula, vy. Martens (Reise, p. 75, 
t. xii. f. 10) quoad formam.” 
L.c. p. 356: “ Habitat Sambelong (Reinhardt); Petite Nicobar 
(Busch, 1845); Kamorta, Teressa, Katchal (Jtoepstorf).” 
* This genus I hope to describe and figure in the next Part. 
