BY R. VON LENDENFELD, PH.D. 527 



V. SUB-GENUS. REGULARIS 

 The connecting fibres are of similar thickness in one and the 

 same portion of the sponge, and the differences in their diameter 

 is never so great as in the foregoing species. The variations do 

 not as a rule exceed 10% of the average measurement. 



The meshes of the network formed by these fibres are also 

 accordingly much more regular. They are small and the connecting 

 fibres are very thin as compared to those of the species in other 

 sub-genera. 



73. SPECIES. EUSI'ONGAI COMPACTA. Carter. 



EUSPONGIA COMPACTA. Carter (1). 



Shape and Size. 



Thin, horizontal or vertical, extending concentrically from a 

 pedunculated or contracted irregular base, terminating at the 

 circumference in an irregularly fissured round margin. Consistence 

 that ot very compact felt. Size, about 11 by 6 mm., in its longest 

 diameter, and 2 mm., thick. 



Colour. 

 Dark fawn when fresh, light fawn or grey after exposui-e when 

 dry ; dermal tissue colorless. 



Surface. 

 Surface uniformly plain on both sides, interrupted only by the 

 pedunculated attachment ; minutely reticulated in relief from the 

 subsidence of the dermal tissue upon the subjacent fibrous structure, 

 which terminates in little conuli, each of which beai"S a sand thread, 

 osculi numerous, small, circular, each provided with an annular 

 diaphragm ; disposed singly or in scattered groups on one side, 

 more plentiful and more or less in juxtaposition on the other ; 



(1) H. J.Carter. New Sponges, Obsei'vations oa old ones, and a proposed 

 new Group. Annals and Magazine of Natural History. 5th Series, Vol. 

 X., No. 56, p. 106, 1882. 



