352 Dr. G. J. Hinde on a true Leuconid Calcisponge 
XLVI.— On a true Leuconid Calcisponge from the Middle 
Lias of Northamptonshire, and on detached Calcisponge 
Spicules in the Upper Chalk of Surrey. By GeorGe 
JENNINGS HINDE, Ph.D. 
[Plate XVII] 
I. Ona true Leuconid Calcisponge from the Middle 
Lias of Northamptonshire. 
Mr. E, A. Watrorp, F.G.S., of Banbury, kindly sent to 
me some time since for study and description several speci- 
mens of a small sponge which he had discovered in the Marl- 
stone beds of the Middle Lias at King’s Sutton, near Banbury. 
The specimens, though small or almost microscopic in size, 
appear to be perfect and full-grown, and their state of preser- 
vation is so remarkable as to permit of ready determination 
of their minute skeletal structures. This is the more sur- 
prising since the specimens prove to be Calcisponges, as 
delicate and fragile as any existing representatives of this 
group. Though occurring in strata of such a comparatively 
remote geological period, the structure of these specimens so 
fully agrees with that of existing sponges of the genus Leu- 
candra, Heckel, that I propose to include them therein. 
Only a single species has as yet been determined, which is 
described below under the name of Leucandra Walfordt. 
Leucandra Walfordi, sp.n. (PI. XVII. figs. 1-9.) 
Sponges small, club-shaped, subcylindrical or compressed, 
slightly contracted at the base, which is attached to small 
grains of sand or fragments of other organisms. Usually 
growing single, but occasionally two or three individuals are 
attached together at their bases. The specimens range from 
2 to 3°5 millim. in height and from °6 to 1 millim. in thick- 
ness. The outer surface is slightly hispid, with obliquely 
projecting spicules; the summits are obtusely conical or 
truncate, without any distinctive neck or spicular collar. 
The cloacal tube extends nearly to the base of the sponge ; 
it opens by a circular or, in the compressed forms, elliptical 
aperture, from *2 to ‘5 millim. in width. The inner or cloacal 
surface of the wall is apparently smooth and without any 
special layer of spicules. The walls of the sponge are about 
*2 millim. in thickness ; they are composed of cylindrical or 
fusiform acerates or rod-shaped spicules and three- or four- 
