

PORIFERA OF THE L.M.B.C. DISTRICT. 169 
coast: Plymouth, Torquay, Guernsey, Diamond Ground 
off Hastings. I may add the Chausey Islands, off the 
Normandy coast, from which locality there is one specimen, 
collected by Professor Herdman in 1882, in the Zoological 
Museum of University College, Liverpool. Tethya lyncu- 
rvwm has been found by Oscar Schmidt in the Adriatic Sea, 
and by Vosmaer in the Adriatic, Mediterranean, and Arctic 
Seas. A description of this well known sponge is not 
wanted. 
C 
SEIRIOLIDA, n. fam. 
The tetractinellid sponge, described below under the 
name Sewriola compacta, appears so different from all 
described forms that I am obliged to found a new family 
for it, the ‘‘Seiriolide,”’ called after St. Seiriol’s Island, an 
older name for Puffin Island. This new family belongs 
clearly to the demus Streptastrosa, Sollas, since Sevriola 
compacta is an astrophorous sponge in which one of the 
microscleres is some form of spiraster. ‘The three families 
of the demus Streptastrosa, Sollas, are now as follows :— 
Fam.1. THENEIDH: ‘‘The ectosome never forms a 
cortex; the mesoderm is a collenchyma; the 
flagellated chambers eurypylous”’ (Sollas).* 
Fam. 2. PACHASTRELLIDZ: “Streptastrosa, in which 
| the chief megascleres are calthrops; triznes 
being absent. The microscleres may be spiras- 
ters, spherasters or microrabds. The choano- 
somal mesoderm is sarcenchymatous and the 
chamber system aphodal”’ (Sollas). 
Fam. 3. SEIRIOLIDZ: The ectosome forms a cortex. 
Chief megascleres trienes. The choanosomal 
mesoderm is cystenchymatous. 
* Sollas, “‘ Report on the Tetractinellide collected by H.M.S. Challenger,” 
pp. 59 and 104. 
