90 Rev. T. Hincks's Contributions towards a 



tlie present form. The cells are cliaracterlzed as " pilose " or 

 " covered with minute pilosities," elongate and narrow, and 

 bituberculate above. 



It is said to form large radiating patches on floating weed 

 off the coasts of Patagonia and Cape Horn. 



The diagnosis, after the fashion of the period in which it 

 was published, is brief and insufficient, and the figure is 

 certainly not a correct representation of M. villosa ; but the 

 salient feature of both is the same. Tlie slender spinules 

 covering the membranous front wall, and giving it a pilose 

 appearance, are present in both forms, and, so far as I know, 

 they are unique. The cells are similar in shape, elongate 

 and rectangular ; but in those of F. IsabeUeana the side- walls 

 are carried up on each side above into a mucronate process 

 which is entirely wanting in M. villosa. In this species the 

 upper margin of the cell is straight and bears on each 

 side a tall acuminate spine. There are also a few small 

 lateral spines, which are absent in the Cape-IIorn species, and 

 also a broad, membranous, strap-like appendage, pointed 

 above, which rises from the centre of the upper margin in 

 many of the cells, and constitutes a curious and very puzzling 

 piece of structure. Round the iniier edge of the cell there is 

 a line of close-set minute spinules. There are said to be two 

 tubercles on the cell below in d'Orbigny's species, of which 1 

 can find no trace in M. villosa. Taking his description as it 

 stands we should hardly be justified in identifying the two 

 forms, though it is possible after all that his species may have 

 been lounded on examples of M. villosa. 



Ibid. (p. 20 Sep.). 

 Membranipora antiqua, Busk. 



The structure of this species and of others kindred to it had 

 not been thoroughly investigated when my paper was written. 

 We are indebted to Dr. Jullien for a valuable contribution to 

 our knowledge of them and a discussion of their systematic 

 position*. He has founded the genus Onychocella for species 

 aoreeing in general character with the Membranipora aiitiqaa of 

 Busk and the family Onychocellidge for this and a number of 

 related forms. While the structural type is fully and ably 

 defined, an unnecessary number of genera, in my judgment, 

 have been created, and undue stress has probably been laid 



* " Note sur uue nouvelle division dus Bryozoaires Cheilostciiiiens,' 

 Bull, de la Soc. Zoologique de France, t. vi., 1881. 



