424 POLYPI. VAGINATI. 



albuminous and gelatinous matter connected internally with anastomosing canals. 

 The skeleton is either simple, consisting of horny fibres, as in the species used 

 for domestic purposes ; or compound, being in this case furnished with calca- 

 reous or siliceous spicula. The gelatinous matter, abounding in transparent glo- 

 bules, connects the different parts of the skeleton, lines the canals, and forms the 

 margin of the pores or openings. The water enters by the pores or mouth, and is 

 ejected by other larger orifices, elevated in some species above the surface in the form 

 of papillae. The ova are numerous, float at first in the water, the anterior portion 

 being covered by ciliae, and finally fix themselves. Dr Fleming in his British Ani- 

 mals arranges the sponges into four genera, Tethya, Halichondria, Spongia, and 

 Grantia, the last after the name of the zealous naturalist who has so successfully in- 

 vestigated the structure of the genus. The first two have their mass supported by 

 siliceous spicula ; the third is cartilaginous ; and the fourth is supported by calcareous 

 spicula. Lamarck's arrangement is followed in this summary. 



1. Masses sessile, simple, or lobed. 



S. commimis, Lam. Sessile, subturbinated, rounded, slightly con- 

 vex above, soft, tenacious, with wide pores ; foramina large. In- 

 habits Indian Ocean. Lam. ii. 353. 



S. lacinulosa, Lam. Sessile, subturbinated, flattish, obsoletely lobed; 

 soft, tomentose, very porous ; surface thickly laciniate. Inhabits 

 Indian Ocean. Lam. ii. 353. 



2. Masses subpediculated, or narrowed at their base, simple or lobed. 



S. angulosa, Lam. Erect, subturbinated, very porous, with lateral 

 angles of unequal forms ; foramina crowded at the margin of the 

 angles. Inhabits seas of New Holland. Lam. ii. 358. 

 3. Masses pediculated, flattened, flabelliform, simple or lobed. 



S. flabelliformis, Lam. Erect, pediculated, flat, suborbicular ; fibres 

 rigid, elegantly reticulated, with waved furrows. Inhabits In- 

 dian Ocean. Lam. ii. 360. 



4. Masses concave, widened, hollowed, or funnel-shaped. 



S. usitatissima, Lam. Turbinated, tenacious, soft, tomentose, very 

 porous ; laciniae slightly scabrous ; concave above. Inhabits Ame- 

 rican seas. Employed for domestic purposes. Lam. ii. 363. 



S. ventilabra, Lin. Widely funnel-shaped, with woody veins ; rough 

 and brittle when dry. Inhabits Northern seas. Wern. Mem. ii. 

 pi. 15, fig. 1. 



5. Masses tubular orflstulous. 



S. tubulosa, Lam. Tubular, branching, fibrous ; fibres sub-naked, 

 reticulated or interwoven. Inhabits Indian seas. Ellis, Zooph. 

 pi. 58, fig. 7- 



6. Masses foliaceous, or divided into flattened lobes. 



S. laciniata, Lam. Leafy, subsessile, soft, white ; laminae many, 

 erect, in bundles, deeply cut ; pores scattered. Inhabits Indian 

 seas. Lam. ii. 374. 



7- Masses branched, ramifications distinct. 



S. arborescens, Lam. (S. rubens, Pall.) Branched, rigid, finely 

 porous ; branches subcompressed, the apex digitate ; foramina 

 distant. Inhabits American seas. Lam. ii. 374. 



S. palmata, Lam. Erect, compressed, very porous ; branches pal- 



