GeiuraJ History of the Marine Polyzoa. 473 



Busk also describes under his G. philomela a variety 

 (adnata) *, leaving it doubtful whether it is referable to this 

 species, or to C. Jigu^aris. It is certainly allied to the latter, 

 but is distinct from it. It has no claim to be associated 

 with C. philomela^ but should rank as a separate species. 



Ibid. (p. 57 Sep.). 

 Crihrilina monoceros^ MacGillivray. 



This species is certainly not a Crihrilina^ as JuUien has 

 already remarked ; it wants the Cribriline structure of the 

 front walk He refers it to a new genus [Arachnopusia) ^ 

 which he makes the type of a family group f- 



The following is his diagnosis : — 



Fan)ily Araclinopusidse, Jallien. 



" Orifice trapezoidal ; frontale perforee par des pores 

 disposes irrdgnli^rement, aux lieu et place desquels on ne pent 

 distinguer d'origelles sur les exemplaires d^calcifit^s et teints 

 an picro-carminate d'ammoniaque ; opercule pellucide, tr^s 

 mince, tr^s difficile k voir, d'une existence douteuse. Ances- 

 trule membraniporoide ^pineuse." 



Genus Arachnopusia, Jullien. 



"Orifice trapezoidal, dont les deux l^vres sont droites ou 

 presque droites ; sur chncun des cotes du trapize que forme 

 I'orifice existe soit une ^pine articul^e, assez ^paisse et creuse, 

 soit un avicellaire plus ou moins facile k voir ; ancestrule 

 membraniporoide a bord libre garni d'^pines. 



" Par I'ancestrule ce genre se rapproche des Mucronella de 

 Th. Hincks." 



Upon this I may remark that the characters adduced as the 

 basis of the family are clearly insufficient and wanting in 

 significance. The orifice is by no means " trapezoidal " as a 

 rule ; it is usually arched above and straight or nearly so 

 below. The absence of " origelles " in connexion with the 

 pores, which are thickly distributed over the front wall, the 

 tenuity and transparency of the operculum, and the structure 

 of the primary cell (" ancestrule ") are the only remaining 

 characters. The last-named is not distinctive, but is common 

 to many widely dithering genera {Microporelln, Schizoporella^ 

 Mucronella, &c.). We know too little as yet of the nature 



* ' Challenger ' Report, pi. xxii. fig. 7. 

 t ' Cap Horn,' p. 02, pi. iii. figs. 8, 9. 



