ASCIDIA XOEMANI. 133 



tlie papillary membranes delicate, very slightly pro- 

 duced. Oral lamina' well developed, ribbed, margin 

 entire; the left oral appendages five or six, denticu- 

 lated, leaf -like, placed diagonally. 



Length sometimes nearly three inches but usually 

 under two inches. 



Hal. Between tide-marks. 



SCOTLAND. Firth of Clyde 

 IRELAND. Strangford Lough, Down (Norman). Bir- 

 terbuy Bay, Connemara, Galway, dredged (More]. 

 First record. Hancock, 1870; coll. Norman [I860]. 



This is a very beautiful species, the test (PI. IV, 

 fig. 3) being of a clear white, delicately tinged with 

 rosy flesh-colour, and when strongly echinated, as it 

 most frequently is, it has a fretted or frosted appear- 

 ance. It is usually attached to Fuel for a small space 

 by the side of the base. The external spines are to a 

 great extent compound. 



The mantle (PL IV, fig. 4) is delicate and trans- 

 parent with a blush, of yellow flesh-colour, and the 

 muscular fibres are slender, and sparsely distributed ; 

 there is no opaque white on either side, except in the 

 region of the stomach which in some specimens is 

 covered with a minute freckling of white or yellow 

 matter. The tubes are wide, and of a rosy hue, par- 

 ticularly at the margin which is occasionally encircled 

 with rose-colour : the excurrent tube is quite one- 

 third down the side ; the branchial is terminal. 



The branchial sac (PI. XVIII, fig. 8) has a few 

 scattered spots of opaque white which are mostly in 

 connection with the suspending vessels ; it is minutely 

 plicated ; the primary vessels are pretty-regularly 

 alternately large and small, but do not vary much in 

 size. The ciliated discs are large and oval ; they are 

 placed on the sides of the vessels and are in pairs 

 between the longitudinal bars ; the discs of each pair 

 are separated a little and diverge forward or towards 

 the oral lamina. The stomata are long, with the ex- 



