Dr. J. E. Gray on the Classijication of Sponges. 447 



zoophyte lias grown. Dr. 0. Schmiilt says it is a parasitic 

 Alga, but I know no Alga of a horny texture ! 



Fam. 3. Hirciniadse, Gray, P. Z. S. 1867, p. 510. 



Skeleton formed of two kinds of horny fibres : — the one 

 thick, and with a central line of broken spicules or grains of 

 sand within, reticulated, forming the base of the skeleton ; the 

 other very slender, forming radiating spicular tufts, which do 

 not anastomose. 



Hircinia^ Sarcotragus, Stematumenia. 



Fam. 4. Dysideids, Gray, P. Z. S. 1867, p. 511. 



Skeleton formed of reticulated horny fibres, with sand or 

 broken spicules of other sponges imbedded in the centre, and 

 covered with a more or less thick coat of horny matter ; brittle 

 when dry. 



Dgsidea. 



B. Skeleton formed of anatomosing filaments having one or 



more series of sjncules in the central line. 



Fam. 5. Chalinidae, /. c. pp. 503 & 511. 



Fam. 6. Phakelliadse, /. c. pp. 503 & 516. 



Fam. 7. Halichondriadse, I. c. pp. 503 & 518. 



Fam. 8. Polymastiadse, /. c. pp. 503 & 527. 



Add: — Quasillina [brevis), Bowerbank. Very like -Ei^?ec- 

 tella, but without hexaradiate and other spines. 



C. Skeleton formed of anastomosing filaments or expanded fin- 



like lohes covered with diverging spicules on the outer 

 surface. 



Fam. 9. OpMstospongiadae, I. c. pp. 503 & 514. 



* Spicules smooth. Ophistospongia. 

 . ** Spicules verticillately spined. Ectyon. 



Order II. SUBERISPONGIA. 



Skeleton massive, composed of sarcode densely charged 

 with simple or pin-like spicules ; without branched excretory 

 system, which is replaced for the most part by areolar cavities 

 inosculating and finally terminating in vents on the surface. 



Fam. 1. Suberitidae. 



Suherita, Spiculina. 



Fam. 2. EapMophoridae. 



JRaphiojjhora, I. c. p. 524 5 Rapjhyras^ I. c. p. 516 ; Osculina, 



