1915. | A. OKA: The Tunicata of the Indian Museum. 13 
ted by Dr. Willey off Lifu, New Britain, and described by Prof. Bourne in the 
‘{ Quarterly Journal of Microscopical Science ”’ in 1903 (I). In external appearance 
this species looks very much like an Alcyonarian zooid having six pinnately branched 
tentacles surrounding the mouth-opening at the anterior end of the body. In re- 
gard to internal anatomy it agrees with Hexacrobylus indicus far better than H. psam- 
matodes. The intestine forms a loop, with distinct oesophagus, stomach, and intes- 
tine, and there is a globular renal sac lying on the ventral side of the stomach. The 
chief point of difference, which renders the generic separation of the two forms neces- 
sary, is found in the structure of the branchial sac. This organ islikewise much reduced 
in Oligotrema, being nothing more than the widened anterior portion of the alimen- 
tary canal, but its walls are perforated by a number of rudimentary stigmata. 
Fam. CYNTHIIDAE. 
This family is represented in the collection by four species: Cynthia lanka, 
Herdman; C. sluiteri, n. sp.; Rhabdocynthia ceylonica, Herdman ; and Microcosmus 
manaarensis, Herdman. Three of these were collected for the first time by Herdman 
on the coast of Ceylon, and were described in his ‘‘ Report on the Pearl Oyster 
Fisheries”’, 1906 (7). The remaining one, which is new to science, shows a close 
affinity to C. spinosa, Sluiter (15), from the Gulf of Tadjourah on the eastern coast of 
Africa. It is curious to find that out of the four species two are entirely covered by 
a thick coating of sand, which is rather exceptional in this family. 
Cynthia lanka, Herdman. 
(BIT HE.) 
Cynthia lanka, Herdman, Report on the Pearl Oyster Fisheries of the Gulf Manaar. On the 
Tunicata, 1906. 
Locahities.—(1) Palk Strait, 12 fathoms. One specimen. (2) Mergui. One 
specimen. (3) Laccadive Sea, at Station 246, 11° 14’ 30” N., 74° 57’ 15” E.; depth 
68-148 fathoms ; bottom sand and stones; October 15th, 1897. Two specimens. 
In one of the specimens the ridge joining the apertures on the anterior end is well 
marked, and the configuration of the apertures is exactly like those shown in Herd- 
man’s figures. In the remaining three the ridge is only very faintly represented and 
the apertures are simply cross-shaped as in the majority of Cynthia. ‘The sandy 
coating of the test is in one specimen, from Palk Strait, rather thick (about 3 mm.), 
while in the others it is “not thick’’, as given in the original description of the 
species. The branchial and atrial siphons are of nearly the same length, and the 
minute spines lining the branchial siphon are yellowish-green with beautiful metallic 
lustre. The zigzag arrangement of the oviduct connecting the gonads is very con- 
spicuous except in the specimen from Mergui, which also differs somewhat in the course 
of the intestinal loop reaching higher up than in the other specimens. Otherwise the 
internal anatomy agrees pretty well with the accounts given by Herdman. The dimen- 
sions of the four specimens are 30 mm. x 26 mm., 24 mm. x 18 mm., 23 mm. x 
17 mm. , and 20 mm. x 15 mm. respectively. 
J 
