CATALOGUE OF TUNICATA. 7 



with a great ventral projection, and an accumulation of ova and embryos 

 on the dorsal edge. Abdomen long and narrow, swelling at the posterior 

 end where the stomach is placed. A slender stolonial appendage is 

 continued down from the posterior end of the abdomen. The branchial 

 and atrial siphons are well-developed, but not lobed ; they have strong 

 sphincters. The mantle, on the whole, is rather strong and opaque, 

 with well-developed musculature and abundant pigmentation. 



Branchial sac with about 14 rows of stigmata. The transverse 

 vessels are all alike and are moderately wide. They are provided with 

 horizontal membranes. 



Dorsal languets large, triangular, joined to the horizontal membranes, 

 and not united by any longitudinal band. 



Tentacles about 20 in number, and of 3 sizes, the larger ones being 

 long and slender. 



The visceral mass is very long, and is formed chiefly of oesophagus 

 and intestine. The reproductive organs are placed in the loop. There 

 is a large conspicuous vas deferens running up the inner side of the 

 rectum. 



Locality. " Under stones at low tide, Vaucluse, P.J., John Brazier, 

 F.L.S." 



This species in appearance (see PI. Clav. I., fig 1.) is singularly like 

 a Diazona, but differs entirely from that genus in the structure of the 

 branchial sac (figs. 9 and 10). The arrangement of the Ascidiozooids is 

 seen well in fig. 2, in which half of the colony has been cut away ; 

 fig. 3 is one of the clumps. Figures 4 and 5 show the appearances of the 

 right and left sides of the body respectively. The spines on the 

 abdominal portion of the test (fig. 6) are not numerous. Each spine 

 springs from immediately over a test cell, but there are far more test 

 cells than spines. Deeper in the test a few " bladder cells " and other 

 modifications of the test cells are found (fig. 7), while in the basal part of 

 the colony there are very many ramifying stolons (fig. 11) with abund- 

 ance of small buds. The longitudinal muscles of the mantle, which are 

 few and regular on the thorax (see fig. 8, which shows also the 

 distribution of pigment masses), break up over the abdomen, and 

 further back come to be arranged chiefly dorsally and ventrally, about, 

 15 bands on each side of each edge of the body about 60 longitudinal 

 bands in all. There are no transversely running muscles. In the 

 peribranchial cavity were found many large tailed larvae, measuring up 

 to 1 mm. in length of body. 



