118 BRITISH TUNICATA. 



so as to give the surface a tuberculated appearance ; 

 largely attached by the side. Apertures approximated ; 

 nearly terminal, generally margined with a line of 

 crimson or orange. Test (PL XXXVII, figs. 10 and 11) 

 rather thick, firm, yellowish white or brownish, covered 

 with roundish tubercles, the inside bright crimson. 

 Mantle (PL XXXVII, fig. 13) crimson above, fading 

 to pale red or orange below. Tentacles long and 

 slender; the branchial aperture above them crimson, 

 and for some extent longitudinally plicated, the lobes 

 forming an operculum below. Branchial sac white ; 

 oral lamina smooth. Ovarie (PL XLIII, fig. 1) orange- 

 coloured, forming two diagonal rolls on each side, 

 bordered by lobed or clavate spermaries. 



Length from half an inch to upwards of an inch. 



Nab. In shallow water and under stones within 

 tide-marks. 



CHANNEL ISLANDS. Guernsey and Herm; not rare 

 (Alder ; Brady $ Hodge; Norman). 



First record. 'Alder & Hancock. 



This species varies much in form. Its usual appear- 

 ance is something like a raspberry, but old specimens 

 are sometimes found a good deal elongated and very 

 rugose. It is largely attached, the margin of the test 

 spreading a little in a thin crust on the stone or other 

 substance to which it adheres. 



The reproductive organs are rather peculiar, the 

 ovaries forming two cylindrical rolls, running dia- 

 gonally on each side of the body, and at the sides of 

 these are seen detached groups of obtusely -lobed or 

 slightly-branched male organs. 



Styela variabilis has only as yet been found in the 

 Channel Islands. 



. | 



FIG. 67. Tentacular filaments of Styela obscura. Magnified. 



