SPONGES— KALLMANN. 255 



individuals may sometimes be left only partially included 

 within the completed fibre. (iii.) Owing to the continued 

 growth in stoutness of a fibre, spicules originally lying ex- 

 ternally, but in close proximity to it, might secondarily come 

 to be surrounded at their basal extremity by the fibre-spongin. 

 (iv.) In the superficial regions of the sponge, spicules which 

 appear as if echinating, are often nothing more than the 

 axial spicules of incipient connecting fibres ; this occurs most 

 frequently when the connecting fibres are unispicular. (v.) It 

 sometimes happens that the development of a connecting fibre 

 — say, an unispicular fibre — proves abortive, the fibre then 

 appearing as a process from its supporting main fibre ; in such 

 a case, if the process were very short, its axial spicule would 

 .appear to echinate the main fibre. 



In the species of Ophlitaspongia described herein, the echi- 

 nating spicules appear to arise in one or other of the ways 

 indicated. 



Dendyi has remarked that his Siphonochalina bispiculata 

 ■resembles an Ophlitaspongia save in the fact that the spicules 

 .are oxea ; perhaps this species should be placed in the genus 

 JDiplodemia, Bowerbank. 



Ophlit.aspongia confragos.\, sp. nov. 



(Plate xxxv., fig. 2, and fig. 53.) 



Sponge small, delicate; of indeterminate hah it ; 

 probably consisting, in most cases, of compressed, iip- 

 gyoivths arising from a thin encrusting base. Osctda 

 indistinguishable , perhaps absent. Skeleton an irregular 

 suh-renieroid reticidation of thin pauci- or uni-spictdar 

 spongin-fibres, with meshes the sides of which are 

 usually of not more than a spicule^ s length. Ouasi- 

 echinating spicules are of occasional occurrence. Aux- 

 iliary spicules are scattered interstitially — in some parts, 

 sparsely; in others, in dense profusion. Megascleres : — 

 (/.) Straight or {seldom) slightly curved principal styli, 

 cylindrical throughout the greater portion of their length, 

 slightly inflated at the base and gradually tapering to a 

 point, attaining a size of igo x 12 ji; (ii.) auxiliary suh- 

 tylostyli with a maximum size of 300 x 5.5 \i. Micro- 

 scleres: — (i.) Palmate isochelcE 10 ]i long; {ii.) bow- 

 shaped toxa, 80 X 3 ]i in maximum size. 



1 Dondy— Proc. Roy. Soc. Vict., vii. (n.s.), 1895, p. 246. 



