64 THE AUSTKALIAN MUSEUM. 



The upper part of the body in which the Ascidiozooids are placed is 

 of extraordinary extent, and is thrown into a remarkable series of close 

 folds (see PL Dist. II., figs. 111). This folded band-like structure is 

 continuous across from branch to branch of the peduncle, but there is 

 evidence that this continuity is the result of concrescence, since points of 

 junction with more or less perfect union can be discovered (see figs. 3, 7, 

 9, 10, c.). In some of these cases the connecting bridges of tissue are 

 still very small (fig. 3). In one very remarkable specimen (fig. 7) a con- 

 tinuous band with two narrow connecting points stretches between 

 what are apparently two distinct colonies with separate peduncles and 

 bases. In some cases the peduncle is very short and stumpy, in others 

 it is long and slender (fig. 8). The different conditions of branching also 

 give rise to very different appearances of the colony. In some the upper 

 end of the peduncle is flattened and expanded so as to be fan-like, but is 

 not sub-divided (fig. 4). 



The test of the body proper is transparent and very delicate, and 

 very little is present between the Ascidiozooids in adjacent rows. Buds 

 are either produced from, or become early connected with, diverticula of 

 the vascular appendages, and a gradation can be traced from the vascular 

 appendages in the top of the peduncle upwards through the very young 

 Ascidiozooids to the fully-developed forms near the free upper edge of 

 the colony (see fig. 5). The vascular appendages lie in large canals, so 

 that the test of the peduncle, as seen in a transverse section, is reduced 

 to a mere reticulum (fig. 13). The bladder cells and test cells are seen 

 in fig. 14. 



The shape of the Ascidiozooid (fig. 12) is remarkable on account of 

 the very long narrow pedicle connecting the thorax and abdomen. The 

 branchial sac is not long but is rather wide, the stigmata are very long, 

 and the dorsal languets remarkably short (fig. 15). The Ascidiozooids 

 examined were all in a male condition with spermatic vesicles lying in 

 the intestinal loop. 



Colella tenuicaulis, Herdm.,* PL Dist. I, figs. 1 16. 



External appearance. The colony consists of an irregularly pyriform 

 body, or mass (the Ascidiarium) in which the Ascidiozooids are placed, 

 borne on the upper end of a long slender peduncle. Several colonies are 

 united in groups by their peduncles being joined at their lower ends by a 

 slightly branched stolon provided with tufts of adhering rootlets or hairs 



* See Revision, p. till. 



