494 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The connectives, however much they differ in detail, are charac- 

 terized by the fact that they meet the main fibers by triangular 

 expansions perforated by apertures, which represent the connective 

 roots of some other species. I refer to these (pi. 52, figs. 2, 4, C>, 7) 

 as fenestrated expansions. Occasionally a connective is found which 

 meets a main fiber not by such an expansion but by a few distinct 

 roots (fig. 4). Where the connectives are joined by cross bars, the 

 latter (fig. 4) terminate in small fenestrated expansions. And where 

 one connective joins another at an angle, the same kind of connection 

 is made (fig. 4). The fibers then in general have this characteristic 

 way of combining, instead of by roots. They are in general without, 

 or with only very few, mineral inclusions. 



The connectives however differ considerably in detail. The fol- 

 lowing types may be recognized: (a) They arc simple, solid fibers 

 without inclusions, 35-50 pt. thick, passing from main fiber to main 

 fiber and only sparsely interconnected (fig. 4). (b) Thicker con- 

 nectives, apparently formed by the fusion, parallel-wise, of two or 

 three of the thinner ones, occur, sometimes with a few inclusions 

 (spicules) (fig. 7). (e) Union between simple fibers, either parallel- 

 wise or by interconnecting bars, gives rise to fenestrated membranes, 

 which may be quite small or plates of considerable size (figs. 2, 6, 7). 



Skeleton in general is coarse and irregular, the meshes except 

 within a fenestrated plate large, up to and over 1 mm., sometimes 

 reaching 3 mm., in width. There are no special dermal fibers, al- 

 though occasionally a connective is so far out that it happens to be 

 included in the dermal membrane. 



Holotype.— Cat, No. 21324, U.S.N.M. 



Comparing this species with two of the best known Ilircbua forms, 

 H. variaMMs F. E. Schulze and II. foetida (O. Schmidt), it may be 

 said that the main fibers are more " fascicular - than in II. varidbibbh 

 and the connectives more disposed to form reticular (fenestrated) 

 membranes, but this tendency docs not go so far as in II. foetida. 

 where the connectives in general have this character. 



HIRCIXIA VARIABILIS F. E. Schulze. 



Hircinia variabilis V. E. Schtlzk, 1ST!), p. 12. — Lendenfeld, 18£9, p. ~->'u. 



Station D5477, one specimen having the shape of a narrow vertical 

 plate which bears along its lateral edges cylindrical branches extend- 

 ing out at right angles to the plate. The branches evidently have 

 terminal oscula. although the latter are now closed. The shape of 

 the sponge is obviously a variant of the ramose type. Total height, 

 120 mm. 



