Io Memoirs of the Indian Museum. [Voz. VI, 
The musculature of the atrial siphon is simple and regular, being composed of longi- 
tudinal and transverse bands cutting one another at right angles so as to form a 
very regular network. 
. The Tentacles are entirely absent. There is not even a trace of these organs, 
whose much branched and dendritic form is so characteristic of the family Molgulidae. 
The Branchial Sac is in a totally redüced condition. There is, it is true, a more 
or less widened part of the alimentary canal in front of the narrow oesophagus, but 
this region exhibits nothing characteristic of a Tunicate pharynx. The walls are not 
perforated, and there are no stigmata, no endostyle, and no dorsal lamina, if we do 
not count as sucha slight longitudinal ridge immediately below the opening of the 
dorsal tubercle. Besides, there is no demarcation between this part and the oesopha- 
gus proper. The inner surface is perfectly smooth, and the lining epithelium seems 
not to be ciliated. A network of fine blood spaces traversing the wall probably 
subserves the respiratory function. The boundary between the internal wall of the 
branchial siphon and the pharyngeal portion of the oesophagus is very distinct, since 
the former is lined with a thin layer of test, whereas the latter has of course the 
epithelium naked. | 
The Dorsal Tubercle is situated on the dorsal wall of the pharyngeal region just 
below its anterior boundary. It is a simple round pit with scarcely raised lips, con- 
nected by a short canal with the subneural gland lying immediately underneath the 
nerve ganglion. The latter is oval-shaped and is placed at the anterior end of the 
trunk between the bases of the branchial and atrial siphons. It gives off six nerve 
trunks, one to each of the tentacle-like lobes of the branchial aperture. 
The Alimentary Canal consists, as usual, of oesophagus, stomach, and intestine, 
and forms a loop twisted somewhat in the shape of the figure 8. The oesophagus, 
which is fairly long but rather narrow, is directed posteriorly and dorsally and opens 
into the anterior end of the stomach. The stomach is of an elongated oval form, and 
lies obliquely in the hindermost region of the trunk with its hind end looking vent- 
rally and a little towards the left. The wall of the stomach is smooth both inside 
and outside. The intestine, immediately after leaving the stomach, turns dorsally 
and, running along the inner surface of the mantle of the left side, reaches the 
dorsal edge of the body and then turns anteriorly to open into the cloacal cavity 
at the base of the atrial siphon. The anus is somewhat bilabiate with entire margins. 
A rounded pouch-like liver is present, attached to the hind part of the stomach. It 
is a large organ, hollow inside, crenated externally, and placed in the centre of the 
trunk, occupying the space between the stomach and the renal organ. 
The Gonads are symmetrically developed on both sides of the body. The ovaries 
and the testes are separate, and each gland is provided with its own duct. The tes- 
tes, of which there is one on each side, are attached to the inner surface of the mantle 
about half way between the anterior and posterior end of the trunk, and rather near- 
er the ventral than the dorsal edge. Each testis is roughly oval in outline, and is 
composed of a large number of branched seminiferous tubules. The vas deferens is 
extremely short and opens directly into the lateral region of the peribranchial cavity. 
