1921] The Genus Raspailia 55 



styles and strongyles, also generally oxea. Habitus cylindrical, long 

 and slender, branching or not branching. 



The long, slender, cyhndrical habitus, with skeletal framework on 

 the general axinellid plan, and the presence of acanthostyles have been 

 regarded by many (Ridley, Ridley and Dendy, Dendy,) as the chief 

 distinguishing characteristics of the genus. The acanthostyles may 

 entirely disappear but the other characteristics remain, as in subgenus 

 Syringella Ridley (1884, p. 460). Examples are: Raspailia syringella 

 0. Schmidt (1868, p. 10) and the two species described by Ridley^ loc. 

 cit. In R. [Syringella] f aid f era Topsent (1890, p. 12; 1892, p. 124) the 

 habitus is fairly typical, and the dermal skeleton adheres to the R. 

 viminalis type. In R. (Syringella) rhaphidophora Hentschel (1912, p. 

 371), the habitus is typical, save that the branches are generally com- 

 pressed; instead of radial fibres, there are radial partitions (lamellae); 

 dermal skeleton of the R. viminalis type; megascleres, styles, oxea, 

 strongyles; microscleres present in shape of bundles of rhaphides. In 

 R. (Syringella) nuda Hentschel (1911, p. 383) the habitus is typical; 

 axial skeleton with radial fibres; dermal skeleton as in R. viminalis. 

 All these forms make it plain that the general practice with respect to 

 Syringella is correct and that such sponges are really members of the 

 Raspailia group in which the acanthostyles have been lost, and should 

 not be relegated on a technicality to the Axinellidae while Raspailia 

 is referred to the Ectyonidae. Nevertheless Topsent (1904, p. 138) 

 takes this position. Pick's position (1905, pp. 18-19) is different and 

 is not opposed to the argumentation of this paper, for while assigning 

 to the Syringella forms the dignity of a genus, he keeps the latter 

 alongside of Raspailia. 



A consideration of a number of the species usually assigned to Ras- 

 pailia makes it plain that Vosmaer 's generic concept cannot be applied 

 in all of its details, especially in the matter of the dermal skeleton and 

 the greatly reduced radial fibres. On the other hand the slender, 

 elongated, cylindrical shape of body, sometimes branching, sometimes 

 not, on which Ridley and Dendy (1887) laid chief emphasis, while 

 common, is by no means constant. In fact, in this group of forms, as 

 elsewhere, the characters have varied independently during the course 

 of evolution, thus giving rise to several combinations. A generic con- 

 cept of Raspailia, to be useful, must take into account the existence 

 of these combinations, and cannot insist absolutely on the slender 

 cylindrical habitus, dermal bunches of spicules such as occur in R. 

 viminalis, monactinal character of the megascleres, or on the acantho- 



