380 POLYZOA INFUNDIBULATA. 



usually met with. I remarked on these specimens somewhat to the 

 following effect, not at the time recognising them as belonging to the 

 species Valkeria ivibricata, that they represented the species Bovjer- 

 banhia densa, and that it did not always confine itself to the surface 

 of the object upon which it grew, but sometimes rose from it as a 

 separate polypidom. Dr. Johnston remarked upon them, that they 

 represented ' the species in its perfect state.' In another letter 

 Dr. Johnston writes, ' Accidentally viewing your specimens of Bow- 

 erbanhia densa, var. ramosa, it at once flashed on my mind that 

 they were ValJceria imbricata, which is indeed the fact. Botver- 

 bankia densa and Valkeria imbricata, are they not states of the one 

 and the same species 1 Your observations will probably result in the 

 erasure of a spurious species.' I have thus Dr. Johnston's testi- 

 mony in favour of the identity of Bowerbanhia densa and Valkeria 

 imbricata."* 



" I may here observe, that many species of zoophytes, as well as 

 the above, spread over the surface of attachment in a single layer, 

 prior to becoming elevated into separate and independent polypi- 

 doms. This with many species appears to be a law of their growth, 

 and is very obvious in the Flustras." A. H. Hassall. 



28. FARRELi.A,f Ehrenberg, 



Lagenella, Farre in Phil. Trans, an. 1837. — Farrella, Ehrenherg in Ann. and 

 Mag. Nat. Hist, vii, p. 303. — Laguncula, Van Beneden Mem. 5. 



Character. — Polypidom confervoid., creeping, fstular and 

 membranous ; the cells elliptical^ scattered. — Polypes ascidian 

 with the tentacula forming a rather incomplete circle : no 

 gizzard ; ova on exclusion ivithout cilia. 



1. F. REPENS, cells oblong., on a pedicle much shorter than 

 itself ; tentacula twelve. (Fig. 58, p. 253.) A. Farre. 



Lagenella repens, Farre in PhiL Trans, an. 1837, p. 403, pi. 24. W. Tliompson in 

 Ann. Nat. Hist. v. 252. Hassall in Ann. and Mag. N. Hist. vii. 364. — Bower- 



* In the MSS. of W. Thompson I find the following note :— " The first time I 

 gave any attention to this species (Valkeria imbricata) in situ was in Clew Bay, co. 

 Mayo, in July 1840, when it was obvious that Bowerbankia densa, which appeared 

 in quantities along with it, was only its early state. I remarked the same in Round- 

 stone bay soon afterwards." G. J. 



-t* The name Lagenella having been appropriated to an infusorial animalcule in 

 1832, Ehrenljerg applied to the ascidian zoophyte so called the name Farrella, in 

 honour of Dr. Arthur Farre, the discoverer of the genus. Van Benedcn has given 

 its history in an admirable Memoir published in 1845. 



