906 DR. J. RENNIE AND MR. H. WISEMAN ON THE [DeC. 11^ 



The tentacles are very numerous, simple and filifoiin, with very 

 miniite tubercles present on them. They are of two dimensions. 



The stomach is small, and the intestine after leaving it I'uns 

 for a short distance anteriorly, then slopes across the left side of 

 the posterior part of the branchial sac from the ventral to the 

 dorsal edge and is continued anteiiorly as a dark-coloured rectum. 



Sub-Order 2. AscidiaB Compositse Savigny, 1816. 

 Family Botryllid^ Giard, 1872. 

 Sarcobotrylloides wyvillii Herdm. (Plate LXY. figs. 1 3-15.) 



Colony. — Six colonies came luider observation. Each colony is 

 onion- or balloon-shaped, slightly incrusting with, in some cases, 

 a short tapering peduncle. The colonies had been attached to 

 soft slimy-looking debris, which still adheres in places. 



Sizes of colonies ; — 



1. 2. 3. 4. 5. 



Length... 1-15 cm. 0*7 cm. 0*65 cm. 0*7 cm. 0'65 cm. 

 Breadth... 1-0 cm. 0-8 cm. 0-75 cm. 0-85 cm. 0-8 cm. 



The ascidiozooids are aggregated on the upper hemisphere and 

 appear black or very dark purple in the preserved specimens. In 

 their natural state the colonies show " yellow lines on a dark 

 brown ground." There is a fairly definite distribution of the 

 zooids of each colony. Two or three rows of alternating paired 

 zooids are diagonally inclined across the inner surface of the 

 common test, while shorter row^s of paii^ed zooids fill up the 

 intermediate s]3ace and comj)lete the occupation of that part of 

 the hemisphere. 



Ascidiozooids (fig. 14). — The ascidiozooids are not much elongated 

 antei'o-posteriorly and are slightly inclined to the surface of the 

 test. An anal tentacle is present. Of two individuals measured 

 the following dimensions were found : — 



1. 2. 



Length 2-0020 mm. 1-8326 mm. 



Breadth (abdominal) 0-6468 mm. 0-8624 mm. 



Breadth (thoracic) 0-8932 mm. 1 -03 1 8 mm. 



There are also present numerous smaller individuals about half 

 the dimensions of the larger ones. 



The test is gelatinous, and swollen at that part where the 

 colony is congregated. It is transparent or ti'anslucent in places, 

 especially at the peduncular region and round the margin of the 

 colony. Club-shaped vascular appendages with swollen end-bulbs 

 (fig. 15) and filled with blood-corpuscles penetrate the mati'ix of 

 the test and are very numerous. 



The mantle is stout. Muscle-bands form an irregular network. 



The branchial sac is well developed. Longitudinal bars are 

 present internally and divide the inner surface into meshes. 

 The stigmata are straight and there are six in a mesh ; they are 



