106 MR. P. W. BASSETT-SMITH ON [ Feb. 3, 
Pleurobranchid; it was much broken both at the anterior and 
posterior extremities. It differs from C. reticulosws in not having 
the peculiar reticulate appearance and in having a pair of lateral 
lobes on either side of the genital segment. 
The third specimen also appears to be new, and belongs to the 
family Dichelesthiide, the animal resembling most nearly the 
genus Enterocola of Van Beneden (Bull. Acad. Roy. de Belg. 
tom. ix. 2nd ser. p. 151), found by him in the respiratory cavity of 
“ Aphidium ficus,” than any other form I have been able to find 
recorded, 
Mr. Crossland’s specimen appears to be much more degenerate 
from its parasitic habits; the articulate limbs are excessively 
small, difficult to make out, and the ova are carried in long spiral 
thread-like processes in a single series as in the Caligidee, and 
not in dilated sacs. Unfortunately there was only this single 
female specimen for examination. I would provisionally create 
for it a new genus “ Ventriculina,” giving the specific name of 
“‘ crosslandi” in recognition of the collector. 
VENTRICULINA, gen. nov. 
Head small, ‘rounded; neck indistinct; 3 thoracic segments, 
the first amalgamated with the head; genital segments lobed, 
equal in breadth with the thoracic; no dorsal plates; abdomen 
short, biarticulate; external ovaries spiral, ova uniserial; first 
antenne 4-jointed, simple, second antenn 3-jointed ; maxillipeds 
very small. 
Three pairs of minute thoracic limbs, first biramose, second and 
third uniramose. 
VENTRICULINA CROSSLANDI, sp.n. (Text-fig. 12, p. 107.) 
Hab. Zanzibar: from a Sipunculid. 
Total length 4mm. Colour white. 
Head small, rounded in front, broadest behind, from under 
which project the anterior antenne. Thoracic segments three, 
the first united with the head, the genital segments trilobed; the 
whole forming an oblong body without lamellar plates, showing 
five distinct rounded lateral lobes, the last pair being slightly 
wider and more acute. Dorsal surface convex, marked by five 
distinct grooves showing the position of the union of the segments. 
Abdomen biarticulate, narrow, one-sixth the total length, the - 
last joint terminating in two small caudal plates provided with a 
marginal fringe of short bristles. External ovaries long, spiral, 
springing from papille at the angle of the genital segments and 
abdomen. Ova large, arranged uniserially as in the Caligide. 
Anterior antenne 4-jointed, non-setose, the first joint being 
the longest and broadest, rising from the underside of the head 
just in front of the mouth; second, third, and fourth joints 
progressively decreasing in size. 
