518 HYATT'S REVISION OF THE 



4. Another specimen of the same sub-species shows the primary fibres continuous 

 below, coarse, loaded with debris, the connective tissue with a looser mesh and much finer 

 fibres than No. 3. 



Sub-species cerebriformis was found to have fibres of even a grade coarser than those of 

 variety typica of Sponrjin agarichia, sub-species dura, and quite as dark colored. 



1. In some cases excessively loaded with debris, which sometimes was not confined to 

 the axes of the primary fibres, but hung in pieces from the exterior, apparently partly 

 uncovered. Primary fibres are usually arranged in fascicles and bundles. 



2. Primary fibres single, widely sejiarated, connecting fibres placed nearly at right 

 angles to these, but with a small mesh. The primary fibres always, and sometimes even 

 the connecting fibres, loaded v.'ith debris. This last fact becomes of great importance in 

 view of its exceeding rarity, and since it shows that under some circumstances even the 

 generic characteristics of this part of the skeleton are subject to individual variation. 



3. Same as above, but without debris in the connecting fibres. 



4. Same as above ; but the fibres are light colored, and in every essential point like 

 those of gossypina. 



5. Fibres of obscura closely resemble those of the coarser kinds of variety gossypina, 

 but the connecting fibres are larger in proportion to the primaries. 



Sjiongia gossyjrina Duch. et Mich., Naturk. Verhand. Hall. Maatsch. Wetensch., Haar- 

 lem, 1864, 21-2, p. 32, pi. 3, fig. 3. 



The typical variety of this species, visually called the Wool sponge, varies greatly in 

 form. All of these forms, however, are characterized by a peculiar surface. The skeleton 

 rises into large tufts over the entire surfiice, the larger oscula occupying the dejoressions 

 between. Sometimes these are very numerous, the whole interior being very cavernous, 

 and sometimes the structure is much denser, with fewer large openings and many smaller 

 ones scattered between the tufts. Occasionally, the depressions are filled ujj on parts of 

 the sponge, and a surface is presented having no large tufts, but only the small secondary 

 pointed bundles of fibres, which are especially characteristic of this variety. 



The result of this structure is to leave gi'eat hollows, or rather a network of deep tun- 

 nels under the derm, which are apparent only after the drying of the specimens, when 

 they become exposed by the universal contraction and cracking of the skin. The color 

 when living is said by Dr. Palmer to be a shining black. 



Loc, Biscayne Bay, Key West and Nassau, in Soc. Coll. Habitat, from three to sixteen 

 feet, and deeper, the limits not being ascertained. The largest seen was about nine inches 

 high by thirty inches broad. 



Variety dendritica. This I have founded simply upon one form, PI. xv, fig. 6, which is 

 fistulose and branching, each branch having one large aperture at the tip. The surface is 

 ornamented with the usual tufts of fibres and long ridges, as in Spoiigia gram'mea. There 

 are others of similar texture in which the association is fistular, but the form is solid and 

 not branching, though quite long. 



Loc, Nassau, in Soc. Coll. 



Variety ^orosa. These are also compound fistulose forms, but the tubes are widely 

 scattered, short and wide-mouthed, giving the whole a flattened table-like aspect, and the 

 skeleton between is very scantily built. One form of this variety has a denser skeleton 



