io Lightbown, Filaments in the Siphonozooids of Pennatulacea 



KOPHOBELEMNON PAUCIFLORUM, Hickson. 



The mesenteric filaments are here very much coiled up. 

 K. Burgeri, Herklots. 

 K. stelliferum, Miiller. 



L. Leuckartii, Kolliker. 



Filaments are recorded in the siphonozooids of these species 

 (Kolliker 1872, p. 303). The observation on L. stelliferum is con- 

 firmed by Kiikenthal and Broch (1911, p. 523). 



Sclerobelemnon Burgeri, Herklots. 



The filaments are very much coiled up, and in a preparation of 

 the whole siphonozooids, are difficult to identify, being in most of 

 the zooids hidden by the stomodaeum. 



FuNICULINA QUADRANGIJLARIS, Pallas. 



There is some doubt among- writers on this genus as to whether 

 the small zooids without tentacles occuring on the rachis are true 

 siphonozooids or young - autozooids. 



Marshall says of them "They have only two mesenterial fila- 

 ments, viz. those corresponding to the two long filaments of the 

 polyps : like these latter they extend to the bottom of the body 

 cavity. The remaining six mesenteries are present, but their free 

 edges below the stomach are not thickened to form mesenterial 

 filaments." (1882 p. 19). It is further stated however — "in the 

 younger specimens there appears to be a gradual passage from 

 zooids to polypes, though whether zooids are in all cases destined 

 ultimately to grow up into polyps must be left for the present 

 undecided. ' ' Kiikenthal and Broch consider the zooids in question 

 to be siphonozooids (1911, p. 527 and Fig. 100, Taf. XXVIII). 

 In the specimen I examined there appeared to be no transition from 

 siphonozooids to autozooids, and the smallest zooids with no ten- 

 tacles bore well-developed dorsal filaments of typical structure 

 (0.037 m.m. broad) and no others. 



Protoptilum celebense, Hickson. 



In this species the mesenteric filaments are of the coiled type. 



DlSTICHOPTILUM. 



No specimen of this genus has been available for investigation, 

 and having found no reference to the anatomy of the siphonozooids 

 in the literature of the genus, I am unable to make any statement 

 with regard to mesenteric filaments. The species are more slender 

 than Protoptilum but as filaments are so generally found in all these 

 more primitive forms it is probable they occur here also. 



