1877.] FIVE NEW SPECIES OF SPONGES. 463 



with sarcode, which appeared to be in a partially decomposed con- 

 dition. 



The skeleton-structure, like that of the spongious base of 

 Hyalonema mirabile, is composed of irregularly dispersed fasciculi 

 of long spicula; but the fasciculi are less compact in their structure, 

 and amid them tliere are numerous single spicula as irregularly dis- 

 persed as the fasciculi are. The form of the skeleton-spicula in the 

 sponge in course of description is very long, slender, cylindrical, 

 with incipiently spinous clavate terminations ; and intermixed with 

 them there are a few very large and stout acuate ones. The best 

 view of the skeleton-structure is to be seen in portions of the sponge 

 from the inner surface of the cup. At this surface the dermal mem- 

 brane appears to be aspiculous ; but immediately beneath it, in the 

 portion examined, there were numerous groups of sexradiate stellate 

 retentive and defensive spicula, densely packed in detached masses 

 of sarcode. This congregation of spicula in separate masses is pro- 

 bably due to the partial decomposition of a uniform stratum of sar- 

 code in the living sponge in which these minute organs abounded. 

 The sexradiate stellate spicula are exceedingly slender, and average 

 jViTiT inch in extreme expansion. They appear to vary considerably 

 in the number of their furcating spicula — some radii being trifurcate, 

 while others are bifurcate ; and very few have the full number of the 

 furcating radii. 



The interstitial spaces of the skeleton are abundantly supplied 

 with cruciform spicula with cylindrical incipiently spinous radii. 

 The normal form of these spicula is evidently rectangulated sexradiate. 

 The greater number of them are cruciform ; but a considerable num- 

 ber have the fifth ray, or basal portion of the shaft ; and a hvf of 

 them are completely sexradiate. There is a very great difference in 

 size between the two sets of spicula — those, appropriated to the 

 dermal system with attenuated radii, and the smaller and much more 

 abundant ones of the hiterstitial spaces with cylindrical radii, the 

 expansion of the radii of the dermal ones averaging -^-^ inch, while 

 those of the interstitial spaces seldom exceed y|^ inch in the expan- 

 sion of the cruciform radii. 



The minute attenuato-acuate spicula, which are numerously dis- 

 persed on the interstitial membranes, average about -^-^-^ inch in 

 length ; and it appears probable that they are really the radiating 

 spicula broken off from the very numerous sexradiate stellate spicula 

 that are crowded together in such great numbers in the interstitial 

 masses of sarcode. The skeleton-spicula are many of them flexuous ; 

 their average length is -^ inch, while the diameter of a fully 

 developed one measured only -^'-^^ inch. 



The loosely arranged fasciculi of the skeleton-structures of this 

 sponge seem to closely ally it to the spongious base of Hyalonema 

 mirabile ; while the physiological structure of its expansile dermal 

 system with its quaternate connecting spicula, and, to a considerable 

 extent, its anatomical structure, are in perfect harmony with the 

 corresponding parts of the genera Alcyoncelhm, Rossella and Geodia ; 

 and the minute rectangulated sexradiate stellate forms of retentive 



