EEPOKT OX THE TUXICATA. 
349 
bars are both well developed (PL XL VI. fig. 6, tr. and i.l.). The fine transverse vessels 
crossing the meshes (O*'.) are present with great regularity. The stigmata are long and 
narrow, like those of Synstyela incrustans. 
The endostyle is conspicuous. Its course is straight. The tentacles are numerous, 
but none of them are very long. In the first specimen examined there were twelve long 
and about twelve smaller intermediate ones, while in the second specimen there were 
about sixteen larger and the same number of smaller tentacles. The smaller tentacles 
are frequently irregular in position and size (PL XL VI. fig. 7, tn., t7i'.) ; they are some- 
times very minute. 
The prebranchial zone l}ung between the tentacular circle and the peripharyngeal 
band is slightly papillated in places ; it is rather narrow. The peripharyngeal band 
bends posteriorly at the dorsal edge to form a slight triangular peritubercular area 
(PL XL VI. fig. 7) which receives the posterior end of the large dorsal tubercle. In some 
cases this organ is not so exactly antero-posterior in direction as is shown in the figure 
(PL XLVI. fig. 7, d.t.), but is slightly inclined. The aperture is much elongated, and 
is not coiled at its ends. This dorsal tubercle is in a very different condition from that 
of Synstyela incrustans ; it is frequently the case amongst Ascidians that closely allied 
species have very differently shaped dorsal tubercles. 
The stomach is fairly large, but is thin-walled ; the intestine is short. There are a 
large number of small polycarps projecting into the peribranchial cavity. They are of 
rounded or pyriform shapes (PL XLVI. fig. 8, g.), and are not deeply imbedded in the 
mantle ; the ducts open upon small terminal papillse. Most of those examined 
contained ova only (PL XLVI. fig. 8), but a few male ones were also found. No larvm 
were discovered in the colony. 
