380 COLLECTIONS FROM MELANESIA. 



millim. respectively ; the vertical height, viz. to base of uppermost 

 tube, is 30 millim. The surface is darkish umber-brown iu colour, 

 that of the body has a slightly irregularly wrinkled parchment-like 

 appearance, that of the tubes is somewhat wrinkled in the direction 

 of their length, and one of them presents further a somewhat 

 shagreen-like surface, as if beset with very short conuli (scarcely 1 

 millim. high). On dissection it is found that whereas the tubes are 

 chiefly (in the dry state) composed of a horny skeleton, 1-2 millim. 

 thick, the body is a very cavernous mass whose bulk is largely 

 occupied by large canals or chambers, 7-10 millim. wide, opening 

 directly into the bases of the similarly wide tubes, the skeleton of 

 the body thus consisting of trabeculae with smooth, rounded surfaces ; 

 the subglobular appearance of the body is produced by the bridging 

 over of the spaces between these trabeculae by a brown paper-like 

 membrane, which is found on microscopic examination to contain 

 no horny elements, but may or may not enclose a certain quantity 

 of minute foreign bodies (sponge-spicules, &c). 



Examining the skeleton of the body with the microscope, I find 

 from vertical sections that it consists of a close reticulation of solid 

 cylindrical horny fibres, distinguishable as : — (1) primary, stouter, 

 approximately straight and parallel to each other, about "07— "04 

 millim. apart, more or less vertical to the surface, according to 

 position, thickness about - 03-*04 millim. ; and (2) secondary, similar 

 to primary, and more or less vertical to them, but often very ob- 

 liquely placed, thickness about '013— *03 millim.; distance apart very 

 variable, from '14 millim. upwards. Colour of fibre, pale to medium 

 amber-colour. Although single primary fibres do not appear to 

 project in the way strikingly exhibited in the more typical forms of 

 Euspongia officinalis, where they project well above the general sur- 

 face, and where distinct " conuli " are formed by the dermis around 

 their bases, yet the sections show au aggregation and projection of 

 the general skeleton at certain points, apparently representing conuli, 

 but not (in the present state of the sponge) finding expression on 

 the outer surface in the conical eminences which usually occur here 

 in Euspongia. On the tubes the dermis (immediately below a mem- 

 branous substance containing a few foreign bodies) is formed by 

 a very close and regular horny network, composed of primary 

 and secondary fibres, like the main skeleton, but arranged parallel, 

 instead of vertically, to the surface. The proportions of the fibres 

 are about the same, respectively, as those of the main skeleton, but 

 the primaries are only "03- - l millim. apart. All the skeleton- 

 fibres are devoid of sand-core, but are coated (in parts strongly) by 

 the minute strongly refractive brown globules which Prof. F. E. 

 Schulze has considered to be probably of Cryptogamous affinities. 



In two points is this sponge of especial interest, viz. (1) in the 

 almost complete subordination of the general arrangement of the 

 skeletal framework to the largely developed excretory canals ; (2) 

 in the almost total suppression of the "conuli." A further point 

 is the absence of sand -cored fibres. I was at first inclined to sepa- 

 rate it gencrically from Euspongia, as having the large mseandrine 



