Mr. H. J. Carter on the Subsj^herous Sjyonges. 9 



minute rough spicules, beneath which are a number of pores 

 more or less regularly scattered over the whole sponge, with here 

 and there larger ones that appear to be vents. Internal structure 

 dense, amorphous, without any appearance of radiation, con- 

 sisting of a cortex and body only. Cortex hard, compact, com- 

 posed of a thin but firm layer of globular crystalloids in juxta- 

 position, covered externally by the dermal sarcode mentioned, 

 and internally in continuous contact with the body ; pierced 

 by conical or dimpled depressions called "pores," keeping up 

 communication between the exterior and interior of the sponge 

 through several microscopic apertures in the dermal sarcode 

 opposite to them, when this sarcode has not been abraded, but 

 Avhere this has been the case presenting a diaphragm of it 

 pierced by a circular aperture some distance below the sur- 

 face*. Body formed of sponge-tissue supported on intercross- 

 ing spicules, which circumferentially run into a narrow zone 

 of triradiate ones that support the crust, the whole permeated 

 by the excretory system of canals, which, branching and ana- 

 stomosing throughout, communicate to the body a cavernous 

 structure, but not the least appearance of radiation ; finally 

 terminating in the vents at the surface of the sponge. Spicules 

 of the dermal sarcode minute, fusiform, rough or subspinous. 

 Globular crystalloids of the crust for the most part elliptical, 

 elongate, somewhat compressed vertically, and presenting an 

 umbilicated depression on the proximal side, found abundantly 

 in every stage of development in every part of the sponge, 

 but chiefly in the crust, where they are packed together like 

 masonry, and sometimes equally so round the calibre of some 

 of the excretory canals for nearly an inch of their course in- 

 wards. When young, consisting of a minute central point 

 surrounded by a radiating mass of hair-like spicules, which, 

 in advancing towards maturity, become conical externally 

 and, giving place to a clear crystallization of the body inter- 

 nally, terminate on the sm'face in clavate rough extremities or 

 polygonal star-like facets (according to their position in the um- 

 bilical depression or on the convex surface of the crystalloid), 

 separated from each other by superficial fissures. Spicules of 

 the body all smooth and slightly curved, cylindrical or fusi- 

 form, with simply rounded or inflated extremities. Minute 

 stellate spicules abundantly dispersed in every part of the 

 sponge, and consisting of a variable number of conical sub- 

 spinous rays, radiating from a more or less conspicuous 

 central point. Size of specimen figured about If inch in 



* That this diaphragm is a portion of the dermal sarcode seems proba- 

 ble, from the occasional presence in it of the dermal spicule. 



