538 HYATT'S REVISION OF THE 



the surface is pitted with shallow depressions or hollows about one half of an inch in 

 diameter. 



Loc, New South Wales, near Sydney. 



Another form precisely intermediate in texture between these and vaviety pocnlata, also 

 occurs in Coll. Acad. Nat. Sciences, Philadelphia, from Cuba. The form is a flattened cup- 

 shape, with numerous depressions of similar flattened form on the sides ; some of these are 

 so deep that they are really smaller flattened cups, without, however, showing fistular 

 orifices at the bottom of the depressions. 



Yanety 2)ocidata. This variety has a denser skeleton than the tj^pical specimens of this 

 species, but this is due to the closer approximation of the primaiy fibres, and not to any 

 increase in the size, nor to any great change in the arrangement of the fibres. The form 

 is fistulose, but the cup shallow above. The exterior is deeply folded, but otherwise the 

 surfiice is smooth. 



Loc, Phillip's Island, Australia, in Soc. Coll. 



Variety injima. This variety is shov/n by one specimen, locality unknown, but probably 

 New South Wales. It is in the Collection of the Academy of Natural Sciences of Philadelphia, 

 and is a fragment composed of distinct branches more or less completely joined along their 

 outer edges, forming a partially flabellate specimen. This is also very interesting, in so 

 far as it probably shows one of the steps in the growth of the flabellate forms. It suggests 

 the idea that these are primarily due to the lateral anchylosis of a certain nuniber of 

 branches growing in the same jilane, but a more complete suite of sjsecimens is necessary in 

 order to test this view. 



Spongelia enormis Hjatt. 



This species can be distinguished by its peculiar surftice and internal structure. The 

 fibre is rather harsh and unyielding, but not wholly inelastic. The form is flattened, flabel- 

 late, manner of attachment uncertain. Excurreut apertures are all of small size, but 

 very numerous and situated on the lateral ridges, not, as usual, in the channels. These 

 lateral ridges are merely slightly raised alcove the surface, and about 3 mm. or so in 

 breadth. They run in lines radiating from a central axis outwardly, and are ornamented 

 by projecting bunches of fibres, in which, however, the single primary fibre at the centre 

 is hardly so prominent as is usual in Spongelia. They, in fact, resemble those of Spongia, 

 in which the primary fibre is often surrounded and concealed by a bundle of bent second- 

 ary fibres. In the interior, however, the singleness of the primary fibres may be easily 

 determined, so that there can be but little doubt of the true atfinities of the species. The 

 primary fibres, however, are very crooked, and are consequently almost indistinguishable 

 from the irregular netAvoi'k of secondary fibres. There is no apparent order of arrange- 

 ment until the section is seen by transmitted light, then thick confused lines of radiating 

 primary fibres appear. This aspect is enhanced by the sharp angle which the secondary 

 fibres make at their junction with the primaries, their great number and close distribution. 



The channels on the surface are shallow, very numerous, and about as wide as the ridges, 

 and are not pierced by the larger apertures. In fact their existence, and those of the 

 ridges, is probably entirely due to the peculiar linear arrangement of the small excurrent 

 apertures and their accompanying tufts of fibres, which serve to elevate the surface in 

 corresponding ridge lines, and leave the general surfiice of the sponge depressed. This 

 is the only way to account for this otherwise exceptional structure, since in almost all cases 



