SPONGES.-HALLMANN. 



169 



agrees in outward features with C. pitiuilu var. nibni happens 

 to be that one of the two which accords with the typical C". 

 piimila in internal features. One must conclude, therefore, 

 either that Lendenfeld did not examine the structure of the 

 skeleton in his two varieties sufficiently closely to detect their 

 difference, and inadvertently ascribed to the typical variety the 

 skeletal features which belong to the variety nibra ; or that the 

 descriptions are really correct, that his two varieties conse- 

 quently were merely different growth stages of one and the 

 same variety, and that the sponge which agrees externally but 

 not internally with C. puniila is a new variety which Lenden- 

 feld overlooked. The former conclusion is the more probable 

 and the one which I therefore adopt. Both ('. pumila and C. 

 puniila var. rubra are capable of being regarded as varieties 

 •of Crella incrustans since their spicules exhibit all the features 

 characteristic for the species. They may accordingly be named 

 C. incrustans var. puniila, and C. incrustans var. rubra, re- 

 spectively. The following is a description of the the former. 



DescriptioiA — The sponge, as far as known; is encrusting, 

 forming a layer (usually of about 1 mm. thickness) which may 

 spread over a considerable area. The surface is minutely 

 rugged or papillated and, in parts, conulose. The colour is 

 greyish w hite in spirit ; in life, according to Lendenfeld, it is of 

 a rose-tint. Small rounded openings, which may be oscula, 

 .occur here and there at \\ ide intervals. 



The basal layer of spongin, with which the sponge covers 

 the substratum, is densely echinated with vertically-standing 

 acanthostyles. The main skeleton consists of both ascending 

 and descending spicular columns, which might be termed 

 respectively principal and auxiliary columns. The principal 

 columns are single or once or (rarel} ) twice branched fibres 

 running upwards from the base of the sponge, and composed 

 of a spongin-axis with embedded and echinating acantho- 

 stvles, and sometimes in addition containing a few coring 

 smooth oxeotes. The auxiliary columns, which proceed down- 

 wards from the dermal layer, consist entirely of smooth 

 oxeotes without visible cementing material. As a rule, the 

 ascending and descending columns meet at varying distances 

 from the surface, so that there results in consequence compo- 

 site columns, in the lower portion of which the spicules are 

 acanthostyles, in the upper portion, oxea. Frequently, how- 

 ever, the auxiliary columns are not encountered by principal 

 columns, and then sometimes reach to the very base of the 



1 In many respects this sponge resembles the recently described Crella 

 incrustans, var. Tliielei (Hentschel -Fauna Siidwest-Australiens, Bd. 3, 

 p. 345. 



