a General History of the Marine Polyzoa. 311 



is well developed, and the form distinctly turbinate. There 

 is no trace of spines. The avicularium is not unfrequently 

 single and central in this species. 



The present form is worth noting for its beauty and the 

 peculiarity of its appearance, but it has no claim to be ac- 

 counted more than a variety. 



Membranipora pedunculata, Manzoni. 

 (PL XVII. figs. 2, 2 a.) 



M. pechmculata, Manz. Biyozoi foss. Ital. contr. 4 (1870), p. 7, pi. ii. 

 fig. 7. 



Zooscia irregularly massed together, forming a thick white 

 crust, or running out into linear series and disposed in single 

 file, pyriform, oval above, and below narrowing off to a point, 

 so as to appear somewhat stalked, suberect, the cell-wall 

 strongly calcified, dense, smooth, porcellaneous, rising from 

 the base to the bottom of the aperture, where it is highest ; 

 aperture sloping off to the top of the cell, occupying usually 

 about half the front surface, wholly covered in with membrane, 

 oval, with a smooth raised margin, expanded towards the 

 bottom into a rather broad border. Avicularia none. Ocecia 

 "globose, smooth, imperforate" {Manzoni). 



Loc. Ceylon, on weed (Miss Jelly). 



Mange in time. Italian Pliocene deposits, Castell' Arquato 

 (Manzoni). 



The dense white walls are a conspicuous feature in this 

 species. From the base of the aperture the cells taper off 

 rapidly to a point, so as to appear almost pedunculate. In 

 the mass they are suberect ; and the aperture, which slopes 

 upward, is subterminal. When running out in single series 

 they present a very Hippothoa-Yike appearance ; in this con- 

 dition they are often very slightly united, and in some cases 

 are wholly disjunct. Many small rudimentary zooscia are 

 scattered over the colony amongst the normal ceils. 



There would seem to be no material difference between the 

 Ceylon form and the Tertiary species described by Manzoni 

 under the name of M. jiedujiculata, which must therefore take 

 its place in the recent fauna. 



Membranipora polita, n. sp. (PL XVII. fig. 1.) 



Zocecia disposed in regular transverse rows, of a solid, white, 

 smooth, ivory-like material, expanding above and tapering 

 off downwards, separated by very distinct narrow sutures, 

 very prominent in front, usually with a smooth umbonate 

 swelling immediately below the aperture, often much grooved 



Ann. & Mag. N. Hist. Ser. 5. Vol. vi. 27 



