ASCIDIA DEPRESSA. Ill 



14. Ascidia depressa Alder and Hancock. 

 (PL VII, figs. 6-8 ; PI. XVII, fig, 11 ; PI. XIX, fig. 8.) 



Ascidia depressa ALDER and HANCOCK in Trans. Tyneside 

 Nat, Field Club, I [1848], p. 201; FORBES and HANLEY 

 Brit. Moll. II [1849], p. 273 [; ALDER in Rep. Brit. 

 Assoc. 1866 (1867), p. 208; NORMAN in Rep. Brit, Assoc. 

 1868 (1869), p. 302]. 



Bod [i oblong-ovate, very much depressed, pale green, 

 attached laterally throughout its entire length by a 

 distinct expansion or disc surrounding the whole. 

 Apertures distant with small red ocelli ; the branchial 

 aperture terminal, the anal on a slight bulging about 

 two thirds down, rather inconspicuous. Text trans- 

 parent, granular or minutely tuberculated on the upper 

 surface, and thickened towards the disc ; under or 

 attached side smooth and very thin. Mantle yellowish 

 green ; of a deeper colour inclining to orange on the 

 lower part. Tentacular filaments numerous, in more 

 than one row. l!r m'Jiidl xae with obtuse papillae. 

 [Oral lamina wide, ribbed on the right side.] 



Length about an inch. 



Hal). Attached to the under-side of stones between 

 tide-marks (and sometimes extending to deep water ?) . 



ENGLAND. Common on the north-eastern coast. 

 [Falmouth, Cornwall (Cnrl-x, 1849).] Isle of Man 

 (Aider). 



SCOTLAND.- -Hebrides (Alder, 180(3). [Island of 

 Housay, Out Skerries, Shetland, at low water (X<>'rin<n/, 

 1868).] 



IRELAND. C onnemara, G-alway (Brady) . 



First record. Alder and Hancock, 1848. 



The test of this species (PL VII, fig. (3) exhibits 

 numerous blood-channels, the ultimate twigs of which 

 are minute, and have their extremities rounded, but 

 not enlarged. In old specimens the tubercles some- 

 times become nearly obliterated and the surface is 

 strongly wrinkled. 



