60 
VINE : NEW OR BUT LITTLE KNOWN EOCENE POLYZOA. 
the lamina, slightly calcified, intact, with a semicircular aperture at 
the top, triangular hollows immediately above the aperture. Com- 
munication pores : in rare cases three, especially in the Colwell Bay 
example ; in the Fareham examples, two, placed in the side walls at 
the distal and proximal extremities of the cell. 
Horizon : Oyster Beds, Colwell Bay, on oyster shells, (Prof. 
Judd), Bracklesham Bay ; London Clay, Highgate (Busk) ; Walton- 
on-Thames (C. D. Sherborn) ; Fareham, on Turritella, Voluta athleta, 
Soland.. and Strepsidura pyrus, var. bulbus ; Portsmouth, Natica 
hautoniensis. 
In all probability the present forms ; when in their natural state, 
were furnished with delicate spines on the walls of the cell, of which 
the remaining beaded, or granulated, surface may be indicative. 
The species, however, must not be confounded with Biflustra Lacroixii, 
Smith, which Hincks gives as a synonym of M. Lacroixii, and Busk 
(Challenger Rep., p. 63) as probably synonymous with Membranipora 
crassimarginata, Hincks, variety B. incrustans, Busk (Chal. Rep. 
p. 63, pi. 15, fig. 5.) 
2. Membranipora holostoma, Busk (Crag. Pol., p. 36, pi. 3, fig. 3) 
var. perforata, var. new. 
Zoarium encrusting ; irregular. Zooecia oval, and occasionally 
pyriform ; front of cell slightly arched ; margins much raised and 
forming a line of separation between the margins of contiguous cells ; 
surface of lamina coarsely perforated ; orifice semi-orbicular ; peri- 
stome not prominent; a circular pore much larger than the perforations 
on each side just below the orifice. Avicularia (?) 
Locality, &c. : on Voluta athleta, Sol. ; Barton Clay, adherent 
to Lichenopora Mediterranea, Blainville, which has already been 
described. 
Membranipora holostoma is described by Busk from a fragment 
found on the inside of a small Pectunculus glycimeris, and the species 
seem to be somewhat rare in the Crag. Dr. Manzoni (Castrocaro, 
p. 14, pi. 1, fig. 12) describes and illustrates a fragment which he 
says is rare, but more like the Eocene form than that of the Crag. 
Reuss (Miocene d' Austria et Ungheria), also catalogues a species 
which he identifies with M. hololostoma, Busk. 
