306 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



larger than usual. On the left side of the endostyle there 

 are only three rows before the ventral fold of. that side is 

 reached. The stigmata are much wider than the fine 

 longitudinal vessels between them. They are regularly 

 arranged, and have straight sides with rounded ends. 



The Endostyle is rather narrow and inconspicuous. 



The Tentacles are exceedingly small. They are of two 

 sizes, placed alternately. There are twelve or fourteen larger 

 and the same number of smaller intermediate ones. 



The Alimentary Canal is small. The stomach is ellip- 

 soidal, and has slight longitudinal folds. The intestinal 

 loop is narrow. 



The Reproductive Organs are in the form of polycarps, 

 partly embedded in the mantle and projecting into the peri- 

 branchial cavity. 



A single specimen of this new species of Polycarpa was 

 dredged on August 1st, 1885, off Port Erin, Isle of Man, 

 from a depth of fifteen fathoms. In external appearance (see 

 PL V, fig. 1,) it is rather like one of the Molgulidse, as the 

 test is incrusted externally with pieces of stone and frag- 

 ments of shells, etc. There are no branched hairs, the 

 incrusting foreign objects being merely attached to the sur- 

 face of the test or partly embedded in its substance. The 

 apertures are distinctly visible, and by their quadrangular 

 shape show at once that the Ascidian belongs to the Cyn- 

 thiidse, not the Molgulidte. 



The pale grey test is rendered stiff by the attached 

 stones ; when these are removed it is weak and flexible. 

 The musculature of the mantle (PI. V, fig. 4), is not divided 

 into separate layers, as it is in many Cynthiidae, but merely 

 forms a dense reticulum of very delicate muscle fibres. No 

 definite bundles are formed except on the branchial and 

 atrial siphons. The ectoderm is very distinct (PI. V, 

 figs. 2, 3). 



