198 | Dr. G. J. Hinde on Fossil Calcispongie. 
well-defined anastomosing bands from °12 to *17 millim. in 
width, of a dark tint, in which are seen numerous delicate, 
closely arranged, and for the most part parallel thread-like 
bodies, distinguished by their lighter outlines. These spicules 
appear, at first sight, to be simple uniaxal forms; but on 
close inspection, in places where they are less closely packed 
together, one or two can be seen to be geniculated and to 
possess a minute projection in the centre, representing the 
atrophied basal ray of triaxal spicules, similar to the spicules ~ 
of the fibre of the preceding species. The difficulty of ob- 
serving the minute basal ray of these spicules in thin sec- 
tions might easily give rise to error respecting the character 
of the spicules, as they would be mistaken for uniaxal forms. 
~ In external form this species is allied to Corynella (Disthe- 
les) excavata, Roemer (Pal. Bd. xiii. T. 1. f. 19), and C. 
(Distheles) depressa (Fromentel, Introd. T. 1. f. 7); but its 
walls are considerably thicker, and both the individuals and 
the compound form are notably larger. 
Horizon and Locality. Upper Greensand, Warminster , 
Wiltshire. 
Collection. British Natural-History Museum (Baker coll.). 
Sestrostomella rugosa, Nn. sp. 
(COE Os nie SUE SUIS ines TENS) 
Sponge compound, growing in upright bushy masses, con- 
sisting of several individuals, from conical to cylindrical in 
form; united at their bases, and occasionally laterally, but 
with free summits. The typical specimen is 68 millim. in 
height, and 76 millim. in greatest breadth. The individuals 
are about 12 millim. in thickness. The lower portion of the 
specimen figured appears to have been enveloped im a compact 
rugose external membrane. The summits of the individual 
sponges are either rounded or truncate. The external surface, 
save in the lower portion of the specimen, where the compact 
membrane is present, is extremely rough, and exhibits an 
irregular open network of coarse fibres. From the summits 
of some ot the individual sponges, well-defined deep open 
canals extend downwards. The cloacal aperture, where pre- 
sent, is about 2 millim. in width; but in some individuals it 
seems absent, and the summit only shows the interstitial 
apertures between the fibres ; but the open canals are present, 
just the same as in the individuals with a distinct cloacal 
aperture. 
I have not detected any dermal spicules in this species, and, 
considering the rough character of the exterior, one could 
hardly expect to meet with them. But though unsuitable in 
