BY 



F. KALLMANN. 641 



Rhaphoxya, gen.nov. 



Defi7bilio)i. — Axinellida?(?) of massive habit, without surface- 

 processes other than in the form of small, typically papilliform 

 conuli; with a rather meagre main skeleton consisting of an 

 irregular reticulation of slender, non-plumose, longitudinal and 

 connecting fibres, somewhat scantily provided with spongin; and 

 without a dermal skeleton. The megascleres are more or less 

 curved to flexuous, slender cylindrical styli, oxea and strongyla, 

 differing from one another only in the character of their extremi- 

 ties. The microscleres are trichites, in dragmata and scattered 

 singly. 



Type-species, R. typica, sp.n. 



The two species which I ascribe to this genus, while scarcely 

 distinguishable from one another in their skeletal structure and 

 spiculation, nevertheless differ so markedly in some other respects 

 as to render it questionable whether their resemblances may not 

 merely be due to convergence. In one of them, for example, — 

 described originally by Dendy as Rhaphisia pallida, — the main 

 efferent canals are surrounded by a broad zone of gelatinous- 

 looking collenchymatous tissue, precisely similar in appearance 

 to that occurring in the same situation in most of the species of 

 Tedaniinc'B I have examined; whereas, in the other, the extra- 

 choanosomal layer of tissue bordering the canal is, as usual, com- 

 paratively narrow, and appears to be histologically different in 

 constitution. The arrangement of the dermal pores also is very 

 dissimilar in the two species; and, furthermore, oscula are ap- 

 parently absent in the one, while present in the other. I am 

 strongly inclined to think that the feature in which R. pallida 

 resembles the Tedaniinjt^ is evidence of its very close relationship 

 to that group; but its microscleres, it must be confessed, afford 

 no confirmation of this view, for they are perfectly smooth and 

 quite symmetrically diactinal, whereas in all the species belong- 

 ing indubitably to the Tedaniinoe that have so far been described, 

 the rhaphides (onychetpp) are not only without exception more or 

 less spinulous, but they are usually (perhaps invariably) also 

 anisoactinal, and are very frequently provided with a bulbous 



