EEPORT ON THE TUNICATA. 
65 
more. There are six or seven stigmata between the dorsal lamina and the first internal 
longitudinal bar (PI. IV. fig. 3), and about the same number (in the middle of the sac) 
between the endostjle and the third bar, so that altogether there are about twenty 
stigmata in one of the longest rows of a fully developed sac. The stigmata are 
verv regular, and are usually wider than the fine longitudinal vessels. They are 
often wider than is shown in the figure (PI. IV. fig. 3, sg.). The endostyle is rather 
narrow. 
The eight tentacles (PI. 1\. fig. 2, tn.) are usually all of the same length, but in some 
cases four of them are shorter, the long ones being the dorsal and ventral and the two 
median lateral tentacles. The latter pair are never larger than all the others, as they are 
in von Drasche’s Polycijchis violaceus. The dorsal tubercle (PI. IV. fig. 2, d.t.) is 
decidedly small and inconspicuous. It is placed much nearer to the dorsal lamina than 
to the tentacles. There is no well-marked peritubercular area. The figure formed by 
the peripharyngeal band is pyriform, with the narrower end ventral. The anterior 
extremity of the endostyle is further from the branchial aperture than the anterior end 
of the dorsal lamina is. 
The alimentary canal is fairly compact, and lies alongside the posterior one-fourth 
or so of the branchial sac. The oesophagus runs posteriorly and ventrally with a slight 
curve. The stomach is not very large. It is ovate in shape, with the intestinal end 
widest. There are four or five projecting folds on each side. The intestine runs 
anteriorly and then turns dorsally, and, touching the anterior wall of the stomach in its 
whole course, reaches the oesophagus, where it turns anteriorly again and runs forwards 
as the rectum for a short distance along the dorsal edge of the branchial sac (PI. IV. 
fig. 3, r). The anus opens into a considerable cloaca, the dorsal part of the peribranchial 
cavity, and this communicates with the common cloaca! cavity of the system by the 
bulbous prolongation of the mantle already described (PI. IV. fig. 3, at.). The anus is 
curiously shaped. The rectum narrows considerably at the top, to form a neck, above 
which the margin of the anus expands into a more or less flattened disk with an 
irregularly crenated margin. Figure 4 shows the top of the disk and the small jmckered 
anal aperture as seen from above ; figure 5 shows another specimen seen from the side 
and in optical section ; while figure 3 represents in surface view, as seen from the side, 
an anus where the disk had only two marked crenations, thus giving it rather a bilabiate 
appearance. 
The reproductive organs are, contrary to the rule in most of the Botryllidse in the 
collection, hermaphrodite. They consist in the fully developed Ascidiozooid of one or 
two large yellow ova and an irregular group of spermatic vesicles. They are placed in 
the usual position on both sides of the body. 
Pp 9 
(ZOOL. CHALL. EXP. — PART XXXVIII. 1885.) 
