ASCIDIA AfTLEATA. 115 



tions of the branchial sac and sigmoid intestine. Ten- 

 tacular filaments numerous, long, and slender. Bran- 

 dial sac with large primary and also secondary papillae, 

 the stomata long and rectilinear. [Oral lamina ribbed 

 on the left side.] 



LeiKjtIt an inch to an inch and a half. 



flab. From between tide-marks to deep water. 



ENGLAND.- -Tor Bay, Devon (Alder). 



SCOTLAND. Lamlash Bay, Arran (Carpenter}. 



IRELAND. Strangford Lough, Down (Thompson). 

 Connemara, Gal way (Brady). Ban try Bay, Cork 

 (Norman). 



CHANNEL ISLANDS. Guernsey (Norman). 



First record. Alder, 1S03 ["; coll. "many years 



"i 

 ago ]. 



The test (PI. VII, fig. 9), which is thin, firm, and 

 transparent, is richly supplied Avith vascular rami- 

 fications, the minute terminal twigs having their 

 extremities simply rounded. 



The muscular fibres of the mantle (PL VII, fig. 10) 

 are not very numerous and are irregularly disposed. 



The walls of the branchial sac (PI. VII, fig. 11, and 

 PI. XVIII, fig. 1) are minutely plicated, and the 

 secondary vessels are rather long, the stomata being 

 elongated and rectilinear with rounded extremities ; 

 the primary vessels are comparatively delicate, and 

 placed further apart than usual. The longitudinal 

 bars are rather more numerous than the plications, and 

 they support at the intersections large, conical papillae, 

 generally with small ones between them ; towards the 

 apex of each papilla, which is rounded, there is at either 

 side a prominent tubercle, below which the papillae 

 widen downwards to the base. The extremities of the 

 papilla?, moreover, are curved downwards or involuted, 

 and thus the profile is fiddle-head-shaped ; the papillary 

 membrane is not largely developed. The oral lamina 

 (PL XIX, fig. 9) is wide with the right side ribbed, and 

 the margin of the left or smooth side is minutely and 



