148 BULLETIN OF THE BUREAU OF FISHERIES. 
the genus is not distinguishable from Hymeniacidon, which he continues to place in 
the Axinellide. Hentschel (1912, p. 355) retains the genus and follows Topsent in placing 
it in subfamliy Mycaline (Esperelline auct.) in the Desmacidonide (= Poeciloscleride 
Tops.). It seems to the writers that Topsent’s treatment is the correct one. 
Esperiopsis Carter. 
Habitus varies; incrusting, amorphous, and more or less upright forms occur; 
the latter may be leaflike or subcylindrical and branching. Spongin commonly pre- 
sent, the amount varying. Skeleton varies from a state in which there are well-developed 
spiculo-fibers, with abundant spongin, to a renierine or halichondrine condition. Mega- 
scleres, styles, some of which may undergo the strongylate modification, often with 
tylostyles. Microscleres, isochele, which may be accompanied by stigmata, toxe, 
or forcipes. 
Esperiopsis obliquan.sp. (Pl. LX, figs. 20 to 23; Pl. LXVI, fig. 58a, b, c, d, e, f.) 
Five specimens; three collected on Fort Macon beach; one dredged just outside Beaufort Inlet; 
one dredged on the “‘ Fishing Bank”’ off the inlet. 
Sponge is ramose; the branches cylindrical or subcylindrical, smooth or knotty, sometimes dis- 
tinctly compressed, commonly 4 to 6 millimeters in diameter. The main branches arise from a base and 
themselves branch. Fusion takes place sometimes between contiguous branches. Sponge may be 
vertical, or the branches may extend out in various directions from the base. The upright speci- 
mens range in height from 60 to 200 millimeters. A specimen with spreading branches has a greatest 
diameter of 50 millimeters. Sponge firm, but compressible and elastic. Color bright red. 
The known specimens show three fairly distinct types of habitus. But as no definable skeletal 
peculiarities are associated with these differences of the exterior, the types are, doubtless, only indi- 
vidual forms, reached as a result of particular growth and differentiation responses that are called out 
by the local environment. In one type (Pl. LX, fig. 21) the habitus is chaliniform. The branches, in 
general, are long, slender, cylindrical, smooth, and taper terminally. In one of the two specimens 
of this type a few lobes are slightly knotty here and there. Inasecond type (Pl. LX, fig. 20) the distin- 
guishing features are the knotty charactemof the branches and the biseriate arrangement of the oscula. 
In a third type the branches are smooth but enlarged terminally, clavate or spatulate. This type is 
represented by the specimen with spreading branches and less well by a small specimen 60 millimeters 
high, which, perhaps, was vertical. 
Dermal membrane thin, perforated everywhere with pores which lie in the meshes of the dermal 
skeletal reticulum. Actual diameter of pores in preserved specimens varying, often 20to soy. Dermal 
surface shows to the eye or lens the outer ends of small cylindrical afferent canals which pass radially 
inward; these appear as circular areas, mostly 175 to 300 » in diameter, abundantly scattered over the 
surface and covered in by the thin dermal membrane. The area of membrane covering in such a canal 
usually shows about three pores. 
Cscula small, 1 millimeter and less in diameter, scattered without order or arranged more or less 
definitely in longitudinal rows, which may be biseriate, viz, two rows on each branch opposite one 
another. In the larger chaliniform specimen (Pl. LX, fig. 21) only one branch shows anything of this 
regularity in the location of oscula. On this branch a biseriate arrangement appears, but it is vague; 
that is, irregular. In another specimen of the chaliniform type and in one of the clavate-spatulate type 
the oscula are arranged in short, irregular, longitudinal rows, but a biseriate arrangement is not present. 
In the specimen with knotty branches (Pl. LX, fig. 20) the biseriate arrangement is distinctly developed 
on almost all the branches, the oscula of a row lying 1 to 5 millimeters apart. 
Embedded in the tissue of one of the specimens are numerous embryos containing many imma- 
ture spicules. A good many sand grains and some large, broken, foreign monaxon spicules are embedded 
in the outer part of the body in the case of several specimens. 
Spicules (P1. LXVI, fig. 58a, b, c, d, e, f)—Megascleres: (x) Style, the chief megasclere, slightly 
curved, tapering toward base as well as toward point, generally smooth but sometimes spinulate, char- 
acteristically 110 torso pby 6to 10. Slendererones appear, especially in the connectives. Thespinu- 
