530 HYATT'S REVISION OF THE 



whereas, in all the spaces between the orifices and this system of channels the connecting 

 secondary fibres are almost even with the tops of the bundles of primarj;' fibres. 



Loc, Key West., in Soc. Coll. 



I have also received, by the kindness of Prof J. W. P. Jenks, a specimen (PI. XYii, 

 fig. 22) of a distinct form, but which at present I prefer merely to mention in connection 

 with the above. It differs from S. Maynardii, solely in the smaller size of the bundles fo 

 jjrimary fibres, their close ajjproximation, and the greater quantity and density and smaller 

 mesh of the connecting skeletal tissue. The specimen has the fistular form, and the locahty 

 is unknown. 



Stelospongos levis Hyatt. 



The forms (PL xv, fig. 16) of the two specimens examined were rounded and fistular, 

 the height being about 108 mm., and the greatest diameter 70 mm. The whole base of 

 S. 3Iaynard'd rested upon the rock, whereas this specimen has a thick, short pedicle, and 

 the walls of the fistular aperture are thin and fringe-like, instead of thick, as in Mmjnard'd. 

 In the skeletal structure there can be no close comparison, except in the generic char- 

 acteristics. The radiating primary fibres form flattened, fan-like expansions, which are 

 particularly noticeable on the sui^face. The reticulations are more generally open or 

 ladder-like than in 3Iaynardu, and the whole, as well as the connecting net of secondary 

 fibre, much finer and denser than in that species ; and the incurrent tubes more numerous 

 and closely set, and less distinctly divided by the tissue of connecting secondary fibres. 

 The apertures are not connected by any special channels, and the surface is therefore even, 

 though roughened by the projecting fan-like tufts of primary fibres. 



Loc, Pacific Ocean, U. S. Ex. Exp., in Yale Coll., and New South Wales, in Coll. Acad. 

 Nat. Sciences, Philadeli^hia. 



Variety rotundus. The two specimens (PI. xvii, figs. 23-24) examined were erect upon 

 short, thick, peduncular bases. One, however, has a gibbotis fistular form, though the 

 central aperture is quite small, and is accompanied by several smaller ones running in a line 

 across the summit. The other is broader near the top than at any other part, and has 

 several excurrent orifices irregularly placed, partly on the top and partly on one side. 

 The structure is denser than in typical levis, owing to the close proximity of the bundles 

 of primary fibres. These have, however, the same structure, branching at intervals into 

 fan-like expansions of lattice work, resembling those used by florists for vines and flowers ; 

 they project considerably, and are so closely set that the whole surface has a character- 

 istically shaggy aspect. The tissue of connecting secondary fibi'es is almost as unim- 

 portant and as open as in Ifaynardli. 



Loc, Phillip's Island, off Port Phillip's Head, Australia, in Soc Coll. 



Stelospongos friabilis Hyatt. 



In the single specimen examined, the principal difference lies in the slight distinction 

 between the tissue of the primary fibres and those of the secondary. Both are much finer 

 than in any of the preceding, and present a vesicular aspect. They are also so mingled 

 together in parts of the specimen that the observer fails to distinguish between the primary 

 fibres and the connecting tissue of secondary fibres. The bundles of primary fibres become 

 apparently simjsle lines or columns formed by a denser aggregation of the connecting 

 tissue. In other parts of the same column or bundle the primary fibres can be singled 



