SPONGES COLLECTED IN PORTO RICO. 
401 
Order 4. KERATOSA Grant. 
Sponges in which the skeleton is composed of horny fibers without proper spicules. 
Family SPONGIDiC iPolejaeff. 
Skeleton consists of reticulating fibers with very slender axial core. Flagellated chambers small, 
opening by special canaliculi into exhalent cavities. 
Genus CHALINOPSILLA Lendenfeld (1889). 
Branching, generally digitate Spongidx, with smooth surface and reticulate dermal skeleton. 
Connecting fibers generally unbranched, forming with the simple main fibers a network with square 
meshes 0.2 to 1 mm. wide. Imitating Chalinids. 
Chalinopsilla pilosa, n. sp. 
Station 6080, one specimen. 
Sponge body solid, consisting of two diverging somewhat flattened cylindrical processes united at 
the base. One process has a length of 100 mm., the other of about 30 mm.; diameter varying from 8 
to 17 mm. Both processes have rounded ends. Color a dull purple, pinkish inside. 
Surface with minute conuli, which may be rather vaguely arranged to form ridges. Main skeletal 
fibers protrude slightly, giving surface a pilose character. Pores thickly scattered, leading into small 
rounded subdermal cavities. Small oscula, 1 to 2 mm. diameter, are found on the sides and at the ends 
of the digitate processes. Several of the more conspicuous lead into longitudinal efferent canals, which 
for some distance coufse along the sides of the digitate processes, separated from the exterior only by 
the dermal membrane; latter sunken so that the position of the canal is indicated by a superficial 
groove. 
Skeleton . — Longitudinal fibers lie in the axis, sending off radial branches, which pass upward and 
outward toward the surface. The axial main fibers are about 400 u apart, somewhat closer together 
than the radial main fibers, the interval between which is about 550 p. Axial and radial fibers are 
alike, about 40 n thick, with a granular core about one-third the thickness of fiber, containing spicule 
fragments very sparsely imbedded. Connecting fibers about 24 p thick, without inclusions, meeting 
main fibers with an expanded base, which is frequently perforated. When the perforation is large the 
fiber appears to arise by two roots. In most connecting fibers in a glycerin preparation a very thin 
axial granular core may be indistinctly made out (doubtless universally present). Spongin in both main 
and connecting fibers faintly stratified. Connecting fibers may be quite simple, stretching from main 
fiber to main fiber, thus giving rise to large rectangular meshes. Such meshes may be subdivided by 
the intercalation between two of the main radial fibers of one or two comparatively short radial fibers, 
the resulting meshes being still rectangular. Or the connecting fibers are frequently somewhat bent 
and branched, so as to give rise to irregularly polygonal meshes, commonly with a diameter one-half 
or one-third the interval between the main fibers. 
The radial fibers, as already mentioned, protrude some little distance beyond the surface. The 
most superficial connectives lie in the dermal membrane, and thus form a dermal reticulum. The 
closeness of the meshwork varies greatly. In places the meshes are 200 to 250 )i in diameter, while 
elsewhere the diameter may be three times as great. Fibers of the dermal reticulum are alike and 
somewhat slenderer than the average skeletal fiber, about 20 p in diameter. 
The species resembles C. dicholoma (Lendenfeld, 1889, p. 142, pi. 2, fig. 4; pi. 3, figs. 3, 11) perhaps 
more closely than it does the other species of the genus. It differs from C. dichotoma mainly in the 
character of the surface, in the frequent irregularity of the skeletal meshwork, in the variable character 
of the dermal reticulum, in the greater slenderness of the fibers in general, and in the exceeding scarcity 
of foreign inclusions. 
Genus ETJSPONGIA Broun (1859). 
Skeletal network pretty evenly developed throughout the, in general, massive body; fibers slender 
and meshes very small. Simple main fibers usually with inclusions, and finer connecting fibers without 
inclusions easily distinguishable, the latter branching and continually anastomosing. 
