FARRELLA REPENS. 529 



noticed that within the limits of one colony this organ is 

 in some cases very conspicuous and fully developed, 

 that in others it is destitute of its dark colour, less 

 completely developed, and much less apparent, while in 

 others, again, it seems to he ahsent. He appears to think 

 that this character is hardly to be trusted as a diagnostic. 

 My own experience certainly does not support this view. 

 I cannot remember that I have ever met with a cell of 

 Bowerhanhia imbricata (for instance) in which the gizzard 

 was not well developed and a conspicuous feature. 



I£ it be occasionally absent in species which are usually 

 furnished with it, this exceptional fact would hardly affect 

 its importance as an element of structure. 



The ova are liberated in this genus, according to Van 

 Beneden, through an orifice at the base of the tentacular 

 wreath. 



Farrella REPENs, Farrc. 



Plate LXXYIII. figs. 5, Tj. 



Lagenella REPENS, Favve, Phil. Trans. 1837, 403, pi. xxir. : W. Thompson, 

 N. H. Irelaud, iv. 464 (not L. repens of Hassall). 



BowERBANKiA REPENS, Johist, B. Z. ed. 1, 256. 



Laguncula REPENS, Vcm Ben. Eeeherches &c., " Sur rorganisation des 

 Laguncula" Mem. Acad. Roy. Bruxelles, xyiii. 25, pi. i. 

 and pi. ii. A. 



Laguncula elongata, id. loc. cit. 26, pi. ii. B. 



Farrella producta, Hincks, Ann. N. H. ser. 2, viii. 361, pi. xiv. fig. 10. 



Farrella repens, Johnst. B. Z. ed. 2, 380, woodcut, fig. 58 (after Farre). 



Stem repent. Zocecia oblong, transparent, springing irre- 

 gularly from the sides and upper surface of the stem, 

 pedunculate, the peduncle much shorter than the 

 cell. 



Polijpide usually with 12 tentacles, which are destitute of 

 setae ; occasionally with 10 or 11. 



2 m 



