REPORT ON THE POLYZOA. 



39 



are 



The forms known to me as referable to the genus Cylindrsecium as above defined 



(1) Cylindrcecium giganteum, Busk. 



Farrella gigantea, Bk., Quart. Joum. Micr. Sci., vol. iv. p. 93, pi. v. figs. 1, 2 ; Gosse, 



Mar. Zool., pt. ii. p. 22, fig. 40. 

 Avenella gigantea, Hincks, Ann. and Mag. Nat. Hist., ser. 3, vol. ix. p. 473. 

 Avenella fusca {forma producta), Smitt, Kritisk Forteckn., p. 503. 

 Cylindrmcium giganteum, Hincks, Brit. Mar. Polyz., p. 535, pi. Isxvii. figs. 3, 4. 



(2) Cylindrcecium dilatatum, Hincks. 



Farrella dilalata, Hincks, Quart. Journ. Micr. Sci., vol. viii. p. 279, pL xxx. fig. 7. 

 Avenella dilatata, Hincks, Ann. and Mag. Nat. Hist., ser. 3, vol. ix. p. 473. 

 Cylindrcecium dilatatum (pars), Hincks, Brit. Mar. Polyz., p. 536, pi. Ixxix. figs. 1-3. 



(3) Cylindrcecium fuscum, Busk. 



Farrella fusca, Bk., Quart. Journ. Micr. Sci., vol iv. p. 94, pL vi. fig. 3. 



Avenella fusca, Alder, North. Cat, p. 69; ? Norman, Shetland Polyz., Rep. Brit. Assoc, 



1868, p. 311 ; Smitt (forma simplex), Kritisk Forteckn., p. 503. 

 Cylindraecium dilatatum (pars), Hincks, Brit. Mar. Polyz., p. 537, pi. Ixxvii. figs. 1, 2. 



(4) Cylindrcecium pusillum, Hincks. 



Cylindrcecium pusillum, Hincks, loc. cit., p. 537, pi. Ixxx. fig. 8. 



(5) Cylindrcecium pusillum, var. "dwarf," Hincks. 



Cylindrcecium pusillum, var. " dwarf," Hincks, loc. cit, p. 538, pi. Ixxx. fig. 9. 



(6) Cylindrcecium papuense, n. sp. 



The respective dimensions of the zooecia in these species, so far as they can be made 

 out (mostly from Mr. Hincks's careful figures), are as follows, given in millimetres:— 



1. Cylindrrecium giganteum, 



2. Cylindrcecium dilatatum, 



3. Cylindr<ecium fuscum, . 



4. Cylindrmcium pusillum, 



5. C ijlindriecium pusillum, var., 



6. Cylindrcecium papuense, 



From these dimensions it would seem that the form most nearly approaching that in 

 the Challenger collection is the one named Cylindracium pusilluvi by Mr. Hincks, from 

 this, however, it differs in the uniform diameter of the zocecia, which in the latter 

 become wider or subveutricose below. 



I may take this opportunity of remarking that the form named Farella fusca by me, 

 from specimens collected at Newhaven, Firth of Firth, by Mr. W. Thompson in 1 849, 

 and which is considered by Mr. Hincks synonymous with his Cylindrcecium dilatatum, 



Length. 





Breadth. 



3-5 



X 



0-20-0-25 



0-9 



X 



0-13 



17 



X 



0-2-0-3 



1-3 



X 



0-10-0-13 



0-7 



X 



01 



1-3 



X 



0-10--11 



