NORTH AMERICAN PORIFER^. PART II. 525 



There is, it is true, considerable resemblance to sub-species dura, the true " Hard-Head," 

 but there are also some differences. The surface and structure of the skeleton and fibre 

 are quite distinct. When living the surface probably closely resembles that of /ti.sca and ' 

 dura, since we find here, as in those forms, groups of the round, small, incurrent openings. 



The smoother aspect of the surface where it is covered by the dried skin, distinguishes 

 this variety at once, but the surface of the skeleton is (PI. xvii, fig. 1) broken up by the 

 ridges into hexagonal or angulated cells of small size, which contrast forcibly with the more 

 irregular and broken surfaces of other varieties. This is due to the closer approximation 

 of the primary tufts and ridges which support the membrane. 



Loc, Biscayne Bay, Key West. Habitat, reef, two feet of water at low tide, and deeper. 



Spongia vermiculata Ducli. et Midi. 

 Sponrjia vermiculata 1 Duch. et Mich., Op. cit., p. 35. 

 Spongia lacinulosa Duch. et Mich., Op. cit., p. 35, pi. 4, fig. 4. 



1. The primary fibres are very coarse, numerous, closely set, but not continuous below. 

 They pi'oject, however, in tufts above the surface, and are united by numerous short con- 

 necting fibres. 



2. In several instances in varieties papyracea, nerjligens and mollicula, the primary 

 fibres are continuous below. 



3. The mesh of the connecting fibre is exceedingly small and irregular, giving the 

 sponge extraordinary density and hardness. The primary fibres are continuous, coarse, and 

 loaded with debris, and run across the mesh of the connecting tissue like small ropes laid 

 on thread lace. 



4. Primary fibres in the same sponge sometimes form fascicles or tufts like those 

 described above, and are sometimes single. 



Variety lacimdosiformis. Why Duchassaing and Michelotti should have selected this 

 particular species as the lacinidosa of Lamarck, is not plain to me, since PL IG of Esper 

 only illustrates a very common variation of the surface in Spongia officinalis, and an 

 aspect of this part which might be anticipated in any species. According to Lamarck's 

 first edition, he regards the whole of Spongia officinalis Esper as equivalent to his Sp)ongia 

 lacinidosa, and particularly designates the same localities, the Red Sea and the Lidian 

 Ocean. 



The oscules are numerous, and their prominence gives the whole mass a sub-fistulose 

 aspect. The tufts are developed in the greatest abundance, and are often themselves more 

 or less dendritic. The Avhole aspect of the skeleton is distinct from that of Sp>ongia lignea ; 

 it is not so dense, and the fibres are coarser and darker colored, resembling somewhat in 

 their appearance those of the finer species of Spongelia. 



Loc, Coast of Florida, in Yale Coll. ; Teneriffe, in Soc. Coll. 



Variety vermicidcdiformis. This forms differs from the j^receding variety chiefly in the 

 texture, which is more open, though as stiff to the touch. The fibres themselves are very 

 stiff, as in some specimens of the preceding variety. The surface is apt to be smoother, as in 

 variety levis of Spongia lignea, and the whole asjiect of the mass lighter, very irregular in 

 form, and with oscules not noticeably elevated in the dried skeletons. 



I have called it vermicidatiformis from its resemblance to the description of vermiculata 

 by Duchassaing and Michelotti, with which it may be identical. 



Loc, near Ft. Pierce, mouth of Indian River. Found dried on the beach. 



MEMOIES BOST. SOC. KAT. HIST. VOL. II. 132 



