HALICHONDRIA. 125 



20. H. SERiATA, encrusthifi, the surface plane, smootli, po- 

 rous ; fecal orifices level with the surface, in regular close 

 ranges; spicula si tort, slightly curved, more pointed at one 

 end titan at the other. 



Plate XIV, Fig. 2. 

 Spongia seiiata, Grant in Ediii. Phil. Jourii. xiv. 116. 



Hab. On the under surface of rocks in the Firth of Forth, 

 Dr Grant. Island of Ireland's Eye, off the Dublin coast, Wm. 

 Thompson, Esq. 



Sponge crustaceous, spreading irregularly, homologous, of a 

 fibro -reticular rather compact texture, scarcely friable when dry, 

 inelastic : fecal orifices numerous, rather small, circular, arrang- 

 ed pretty regularly in rows over the even minutely porous sur- 

 face : spicula short, slightly curved, more pointed at one end 

 than at the other. Distinguished from H. incrustans by the 

 regular close ranges of fecal orifices which traverse its flat sur- 

 face, and which are never raised to the extremities of projecting 

 papillae, as in the H. panicea. The spicvUa are similar to those 

 of H. incrustans. 



21. H.?CELATA, amorphous, yelloiv, imperfectly cellular, 

 the surface bored icith numerous circular oscula often filled 

 with a mammillated plug ; spicula shajjed like a pin. 



Var. «. massive and rude. 



j3. sinuous, the shape dependant on the form of the holes in old oys- 

 ter-shells which the sponge occupies and fills. 

 Cliona celata, Grant \\\ Edin. New. Phil. Journ. i. 78: ii. 183, pi. 

 2, fig. 7, (the spiculum.) Fhm. Brit. Anini. 51G. Starlt, Elem. 

 ii. 421. Johns. Brit. Zooph. 305, pi. 42, fig. 5, 6. Dujardin in 

 Ann. des Sc. Nat. n. s. x. 5. 

 La Clione cnchec, Blainv. Actinolog. 327, pi. 94, fig. 7. (Thespi- 

 culinn copied from Crant.) 



