1877.] FIVE NEW SPECIES OF SPONGES. 459 



packed specimens, very uniform in their colour and degree of semi- 

 transparency. These organs varied in diameter from g-o'Tnr ^^ xsVu 

 inch. Some of these groups of gemmules consisted almost entirely 

 of the larger forms, while in others they vyere nearly all of the 

 smaller description. They require a linear power of about 300 to 

 render them distinctly to the eye. 1 have never before seen a similar 

 congregating of the gemmules in any sponge that I have examined. 



The general structure of the skeleton is very irregular, the 

 rete in some parts being composed of many more spicula than in 

 others. The spicula of which it is constructed are of the same form 

 and size as those of the dermis. The gemmules were also dispersed 

 singly around the rete to which they were attached ; and in size and 

 general character they were in perfect accordance with those grouped 

 on the inner surface of the dermal membrane. 



This sponge is the only specimen I have seen of the species ; and 

 although its structural characters are exceedingly simple, its external 

 ones are so remarkable, that it cannot well be confounded with any 

 other known species of Isodictya. 



PoLYFiBROSPONGiA, genus novum. 



Skeleton kerato-fibrous. Fibres solid, cylindrical, aspiculous. 

 Rete symmetrical. Skeleton-lines polyfibrous ; primary lines of the 

 skeleton radiating from the base of the sponge to the distal margin ; 

 secondary lines disposed at nearly right angles to the primary ones. 



Although nearly allied in many respects to the genus Spongio- 

 nella, there is an important difference in the structural arrangement 

 of the skeleton-fibres of this sponge as compared with those of the 

 type forms of Spongionella pulchella, which distinctly separates 

 them. In the latter genus the skeleton-structures, both primary 

 and secondary, are composed of single fibres ; the primary ones 

 radiating from the base of the sponge, and the secondary fibres being 

 disposed at right angles to the primary ones. This mode of skeleton- 

 structure prevails also in the sponge from the Philippine Islands ; 

 but instead of single fibres thus disposed, we find continuous fasci- 

 culi, each composed of numerous slender fibres in both the primary 

 and secondary portions of the skeleton-structures. Thus, although 

 the individual fibres of the sponge are very nearly the same as in 

 Spongionella, the congregation of the fibres in large diffuse fasciculi 

 constitute an important generic difference ; and I therefore propose 

 to make this peculiar mode of skeleton-structure the type of a dis- 

 tinct genus, to be designated as above. 



3. POLYFIBROSPONGIA FLABELLIFERA, Sp, UOV. 



Sponge fan-shaped, pedicel very short, parietes very thin, sur- 

 face smooth and even. Oscula and pores inconspicuous. Der- 

 mal membrane aspiculous, but abundantly supplied with adherent 

 extraneous matters. Skeleton : Primary lines composed of a loosely 

 constructed polyfibrous cord of slender anastomosing keratose fibres; 

 secondary lines constructed the same as those of the primary series ; 



