330 Transactions of the Society. 



the Selsey shore-sands — but for the fact that the same species 

 occurs with tolerable frequency, and very much better developed, 

 both as regards size and condition, in a fossil deposit which we have 

 from Victoria, Australia (Filter Quarry, Moorabool River), stated 

 to be Miocene. This Filter Quarry deposit is a clean Bryozoan 

 shell-sand rich in Foraminifera. We have prepared sections 

 which show that in addition to the ordinary aperture, the species 

 has a number of supplementary apertures in the form of the conical 

 spines, which form rings round the shell and are tubular through- 

 out. Our sections and balsam-mounted specimens also disclose the 

 fact that the species belongs to the group of Bigenerintv for which 

 the late M. Schlumberger proposed the sub-generic name of Sipho- 

 generina. The siphon so-called, however, is not a tube, but merely 

 an internal partition or septum, traversing the central portion of 

 each chamber from floor to roof, and curved in section, correspond- 

 ing with the external aperture, which, in perfect specimens, is a 

 curved slit, and not an oval, as stated by Terquem. 



Length of Selsey specimens, 0*3 mm. Breadth, 0*15 mm. 



Filter Quarry specimens: length, 0'5-0*9 mm.; breadth, 0*25- 

 0*4 mm. Average number of chambers in uniserial portion, six. 



67. Bigenerina selseyensis sp. n. Plate XV. figs. 15-17. 



Description. — Test dimorphous, consisting of six to eight cham- 

 bers arranged on the Textularian plan, followed by two to five 

 chambers in a continuous line. The later chambers oval in section, 

 constricted at the sutures ; aperture oval, with slightly bordered and 

 raised rim. Surface very rough, semi-arenaceous ; traces of spines 

 observable in some specimens. 



Not uncommon in the shore-sands, especially opposite Thorney 

 coastguard station. The specimens, which are all similar in ap- 

 pearance, are apparently derived from a, clay source, probably the 

 Selsey Beds of Clement Beid. The species bears a considerable 

 external resemblance to Bigenerina Schlumbergerii, Millett, but 

 differs from that form in the character of its test, which is rough and 

 semi-arenaceous, instead of hyaline, and in the absence of definite 

 spines. We have been unable to satisfy ourselves as to the presence 

 of an internal siphon. F. Chapman's figure of Sagrina ealcarata 

 Berthelin sp.* is not unlike our form in general contour, but pos- 

 sesses a fringe of spines round each of the moniliform chambers, 

 which is absent in B. selseyensis. 



Length, ■ 4-0 ' 55 mm. ; breadth, ■ 150-0 * 175 mm. ; thickness, 

 0-125 mm. 



* See this Journal, 1898, p. 15, pi. ii. fig. 14, a, b. 



