162 Mr. J. Alder on the British Tunicata. 



nute, crystalline, pointed spicula. Test thick, tough, opake, 

 smooth, rose-coloured, closely adhering to the mantle. Mantle 

 flesh-coloured, opake. Tentacular filaments large, bipinnate. 

 Branchial sac with seven deep folds on each side ; ventral plait 

 smooth, undulated above. Length about half an inch. 



A single specimen of this beautiful Cynthia was procured by 

 Dr.Bowerbank from theDiamond trawling-ground near Hastings. 

 In some of its characters it approaches the C. micro co sinus of 

 Savigny, which Prof. Milne-Edwards informs me is distinct from 

 the C. microcosmus of Cuvier ; but its smooth test, without 

 corrugations, and the absence of any parasitic growth over the 

 surface, forbid our referring it to that species. The small cry- 

 stalline spicula surrounding the apertures are very curious and 

 peculiar. 



Cynthia echinata, Miiller. 



Prof. E. Forbes has referred this species by mistake to Ascidia, 

 and the apertures in his figure (Brit. Moll. vol. i. pi. c. fig. 4) are 

 erroneously represented with six and eight lobes. They are both 

 decidedly quadrate. The branchial sac has six folds on each side, 

 and the smaller meshes have the peculiarity of being transverse 

 instead of longitudinal as in the other species. The tentacular 

 filaments are branched. 



Cynthia mammillaris, Pallas. 



The Ascidia mammillaris of Pallas does not appear to have 

 been recognized by later naturalists. A Cynthia sent me by 

 Mr. Spence Bate from Plymouth, by Mr. Jeffreys from Lulworth 

 Cove, and by Dr. Bowerbank from Hastings, must, I think, be 

 referred to this species, found " on submarine rocks in Corn- 

 wall " by Gsertner nearly a hundred years ago. It is very irre- 

 gular in form, generally transversely ovate, deeply wrinkled, and 

 strongly lobated. The test is tough, thick, and of a dirty yel- 

 lowish colour, generally covered with small Zoophytes and other 

 parasites, and with stones and fragments of shells adhering near 

 the base. The apertures are not far apart, and rayed with red 

 internally : the tentacular filaments are linear ; and the branchial 

 sac has four folds on each side. It therefore belongs, like the 

 majority of our British species, to the third section of Savigny. 

 It appears to be not uncommon on the south coast of England, 

 and may perhaps be the species alluded to by Forbes under the 

 head of C. microcosmus, to which in external appearance it bears 

 some resemblance. 



Cynthia sulcatula, n. sp. 



Body subcylindrical when extended, hemispherical when con- 

 tracted, attached by a broad base. Apertures terminal, on long 



