1876.] DR. BOWERBANK ON SILICEO-FIBROUS SPONGES. 535 



Fig. 3 a, 6 a. Thumb of ditto. 



4, 5. Yiew of side and concave surface of suctorial disk of Thyroptera tri- 

 color, Spix. 



6. Foot of T. tricolor, with suctorial disk, also calcaneum with projections 



from its posterior margin. 



7. Foot and part of the inferior surface of the leg of Mystacina tuberculata, 



Forst. 

 7 a. Thumb of M. tuberculata, showing denticle at base of claw. 



8. Foot of Hemidactylus coct<?i (Geckotida?). 



9. Hind foot of Hyrax dorsalis. 



2. A Monograph of the Siliceo-fibrous Sponges. By J. S. 

 Bowerbank, LL.D., F.R.S., F.Z.S., &c.— Part VI. 



[Received May 31, 1876.] 

 (Plates LVI. & LVII.) 



Deanea favoides, Bowerbank. (Plate LVI. figs. I, 2.) 



Sponge laminar or cup-shaped, thin, resembling a thin section of 

 a honeycomb. Surface even. Dermis thin, translucent, aspiculous. 

 Oscula and pores unknown. Skeleton symmetrical, rotulate ; rotulte 

 confluent ; fibres cylindrical ; central canals large and very distinct. 

 Sarcode dense, opaque, amber-coloured. 



Colour, in the dried state, dark amber. 



Hab. West Indies? {Captain Hunter ?). 



Examined in the dried state. 



This is a remarkably constructed sponge. It consists of a very 

 open reticulate structure, closely resembling a thin slice of the cells 

 of the comb of the honey-bee taken at right angles to the long axis 

 of the cells. The parietes of these large open areas are constructed 

 of a confluent rotulate rete of the same form as that of the skeleton- 

 structure of Deanea virgultosa, described in the Society's ' Proceed- 

 ings,' 1875, p. 275 ; and, as in that species, the fibres are all canalicu- 

 lated and confluent, but the canals are not quite so strongly produced. 

 The external surface and open spaces of the sponge do not appear to 

 be covered with a continuous dermal membrane ; but it covers the 

 interstices of the rotular areas of the skeleton rete, and is in those 

 parts thickly coated with a dense and nearly opaque layer of 

 sarcode. 



The dermal membrane appears to pass inward and to line the in- 

 terior of the large open spaces of the skeleton-structure ; and in no 

 instance could I find even a fragment of the membranous and sar- 

 codous structures projected into the large open areas of the sponge, 

 although upon their parietes it is in a perfect state of preservation. 

 We may therefore reasonably infer that in a living state these great 

 orifices are in an open condition. 



The dermal surface is quite smooth ; and a comparatively thick 

 dense stratum of dark sarcode intervenes between the dermal mem- 

 brane and the siliceous skeleton. 



I have no certain record of the habitat of this species ; nor am I cer- 



