PORIFERA OF THE L.M.B.C. DISTRICT. 39 
interior are in most cases strongyla (0°54—0'85 mm. by 
0012 mm.), besides which there are found also styli of 
the above mentioned kind, and a very few oxea. The 
microsclera are spherasters, with about twelve rays, and 
measuring 0°02 mm. in diameter. Those spherasters are 
found only in the ectosome; they lie very close to the 
surface and are numerous, although they do not forma 
continuous layer. 
Suberites suberea, M. 
Collected at Puffin Island, on the North side, 14th 
January, 1888, and on the South Spit, March, 1888. 
Cliona celata, J. 
Raphyrus griffithsia, B. 
Very common, boring in old shells and in the limestone 
rocks, at Puttin Island. 
Polymastia mammillaris, Johnston (Pl. VI., figs. 1—8). 
Spongia penicillus, Montagu. 
Halichondria mammillaris, Johnston. 
One small specimen of this Sponge was dredged in 
Church Bay, near Holyhead, on the ‘‘ Hyena’”’ Expedition 
of 1886, and it is the first one which has been obtained in 
the L.M.B.C. district, although the species had previously 
been found at many points on the British coast. Johnston 
gives the following localities: coast of Devon, Scarborough 
and Strangford. Bowerbank mentions Larne Lough, 
Guernsey, Shetland, and the Orkney Islands. According 
to Vosmaer,* it is found in the Atlantic, Arctic, Medi- 
terranean and Adriatic Seas generally. The specimen from 
Holyhead has a rounded basal mass of about 7 mm. in 
diameter, and had apparently been fixed to a small stone. 
Four papille are given off, the largest of which is 8 mm. 
* Vosmaer, ‘‘Sponges of the Willem Barrents Expedition, 1880 and 1881,” 
in ‘‘Bijdragen tot de Dierkunde.”’ 
