i io SPONGES 



as a natural family the Pharetronidae, which Dendy wishes to distribute 

 amongst the other Heterocoela. 



GRADE A. HOMOCOELA, Pol., s. ASCONES, H. 



Gastral layer continuous. 



FAMILY 1. CLATHRINIDAE, Minchin. Form reticulate. Triradiate 

 systems always present, equiangular ; rnonaxons present or absent. Collar 

 cells with nucleus at base. Larva a parenchymula. Genera Clathrina, 

 Gray ( = Ascetta, H., pars. Ascaltis, H., pars., etc., and Leucascus, D.) ; 

 Figs. 2, 6, 7, 8 ; Ascandra, H., emend. ( = Homandra, Ldf., for Ascandra 

 falcata, H.) ; Dendya, Bidder, for Clathrina tripodifera, Crtr. FAMILY 2. 

 LEUCOSOLENIIDAE, Minchin. Form erect ; monaxons always present ; 

 triradiates, if present, alate ; collar cells with nucleus apical ; larva an 

 amphiblastula. Genera Ascyssa, H. ; Leucosolenia, Bwk. ( = Ascandra, H., 

 pars., etc.) ; Figs. 3, 4, 5. 



GRADE B. HETEROCOELA, Pol. 



Gastral layer discontinuous and restricted to chambers. 



FAMILY 3. SYCETTIDAE, D. Chambers elongated, radially arranged 

 round the central gastral cavity, their ends projecting on the dermal 

 surface, not covered by a dermal cortex. Tubar skeleton articulate. 

 Genera Sycetta, H., emend. ; Sycon, Risso, emend. (Figs. 9, 10) ; Sy- 

 cantha, Ldf. FAMILY 4. GRANTIDAE, D. With a distinct and continuous 

 dermal cortex covering over the chamber layer, and pierced by inhalant 

 pores. No subdermal sagittal triradiates, nor conspicuous subgastral 

 quadriradiates. The flagellated chambers vary from elongate and radially 

 arranged to spherical and irregularly scattered ones. The skeleton of the 

 chamber layer varies from irregularly articulated to irregularly scattered. 

 Genera Grantia, Fleming (Fig. 11); Ute, O.S. ; Amphiute, Han.; 

 Utelkt, D. ; Anamixilla, Pol. ; Sycyssa, H. ; Leucandra, II. (incl. Polejna, Ldf. ; 

 Vosmaeria, Ldf. ; and Teichomlla, Crtr., Figs. 12 and 71) ; Eilhardia, 

 Pol. (Fig. 13) ; Leucyssa, H. ; Lamontia, Kirk. FAMILY 5. HETEROPIDAE, 

 D. A dermal cortex as in the last. Subdermal sagittal triradiates 

 present. Flagellated chambers as in the last. An articulated tubar 

 skeleton may or may not be present. Genera Grantessa, Ldf. ; Heteropia, 

 Crtr. ; Vosmaeropsis, D. FAMILY 6. AMPHORISCIDAE, D. A dermal 

 cortex as in the last. Conspicuous subdermal quadriradiates, with 

 inwardly directed apical rays, are present. Flagellated chambers as in 

 last. Genera Heteropegma, Pol. ; Amphoriscus, H. ; Syculmis, H. ; 

 Leucilla, H. (including Pericharax, Pol.) ; Sphenopliorina, Breitf. FAMILY 

 7. IPHARETRONIDAE, Z. Skeleton with fibres formed by interlocking 

 of spicules. SUB-FAMILY 1. DIALYTINAE, Rff. With all spicules 

 separate. Genera Lelapia, Crtr. ; *Diaplectia, Hinde [Ool.] ; 

 *Euplocalia, Steinm. [Tr.] ; *Eudea, Lamx. [Tr. Jur.] ; *Colospongia, 



t Fossil and recent. 



