Sponges from South Australia. 115 



as in the typical form. Structure from without inwards, 

 consisting of this compact stratum of fiesh-spicules, passing 

 inwards into a less compact structure composed of sarcode 

 and skeletal spicules, the latter forming a spiculo-hbrous 

 skeletal reticulation of a grey colour, whose interstices are 

 filled up by a yellowish sarcode, and the whole when dry of 

 course not only still more compact, but mealy in appearance 

 and fracture. Size variable, the largest of several specimens 

 7 in. high by 8 x 6 horizontally. 



Depth 20 fath. 



Ohs. This presents the same characters in structure, colour, 

 and spiculation as that on the little crab's back now in the 

 Liverpool Museum, which came from the Mauritius, and to 

 which I have already alluded. 



In both these forms there is a great variety in the size 

 of the spinispirular llcsh-spicule as well as in the form of 

 the head and dimensions of the pin-like or skeletal spicule, 

 of which only those of the largest have been given, since, 

 as may be easily conceived, where the spicules must be 

 small before they are great (like everything in nature), and 

 are continually and successively being formed, this must be 

 the case. 



13. Sjn'j-astrella cunctafrix, VAY. 2Jorcata {dry). 



This specimen appears to have been pyramidal in form 

 when fresh, with a smooth surface, or only slightly charac- 

 terized by the suberitic elevations to which I have alluded ; 

 but now presents a number of thick rugaj running from the 

 base towards the apex, which appear to have arisen from a 

 glue-like nature of the cortical layer, that has thus been 

 thrown into folds whilst drying ; but whether this consistence, 

 of which the less compact structure of the interior more or less 

 partakes, is natural or caused by partial decomposition I am 

 unable to state. Certainly specimens of a similar species and 

 form have passed through my hands ; but then other similar 

 species have, when half decomposed, presented a gluey flabby 

 nature when wet, and a correspondingly compact gluey cha- 

 racter when dry, although still retaining part of their original 

 structure in a glutinized condition. In every other respect 

 this specimen resembles Spirastrella cunctatrix, and has 

 been designated a variety of it under the name ^' porcata^^ on 

 account of the ploughed-field like form of the surface. 



This glue-like character of the sarcode often presents itself 

 in dried specimens. Is it owing to partial decomposition or 

 to a naturally more inspissated condition of the sarcode ? 



