BY E. F. IIALLMANN. 657 



— their terminal spicules (up to 1500 by 15/a in size) projecting 

 beyond; (ii.) of shorter and relatively stouter styli, partly 

 scattered irregularlj' between the main fibres, and partly forming 

 lesser fibres running irregularly in various directions; and (iii.) of 

 slender oxea (up to about 1000 by 6//. in size), which "pflegen in 

 grosserer oder geringerer Anzahl die Style zu begleiten." 



Higginsia natalensis Carter(5). Flabelliform, stipitatc; with 

 thin ridges on both surfaces, radiating from stalk to circumfer- 

 ence. Skeleton-structure undescribed : megascleres of two kinds, 

 viz., (i.) styli (up to about 1000 by -IS/x in size), presumably 

 arranged in fibres; and (ii.) slender oxea (up to 700 by 7/v. in 

 size) surrounding (i.) "in great numbers". 



Higginsia coralloidcs Higgin(17), et varr. More or less lamellar, 

 varying from submassive {i.e., sessile and only slightly com- 

 pressed) to stipitate-flabelliform, and then either entire or palm- 

 ately subdivided; with longitudinal or radiating ridges on both 

 sui'faces. Skeleton consisting of more or less plumose main 

 fibres or columns with an irregular reticulation of spicules 

 between. Megascleres almost exclusively oxea, or oxea alone; 

 usually of two kinds. 



Higginsia thielei Topsent(53). Massive, with irregular surface. 

 Skeleton consisting of "un reseau irregulier, tres solide, de styles 

 robustes disposes par paquets epais et relies aux entrecroise- 

 ments par un lien tres faible de spongine incolore." Megascleres 

 styli, of a single kind. 



In all the species, the microscleres are of the same character- 

 istic form, and occur irregularly scattered through the choano- 

 some and usually also in the dermal layer: they are symmetri- 

 cally and rather sharply bent {i.e., centrangulate or geniculate) 

 acanthoxea with small spines scattered irregularly over their 

 whole length, and are frequently provided with a bulbous dilata- 

 tion situated slightly excentrally. 



The exact similarity which exists between the microscleres of 

 the present genus and those of Halicnemia patera has already 

 been pointed out by Topsent(49), who accordingly refers IlaJio- 

 nem^a, along with Higginsia, to the Axinellidte. It seems to me 



