THE WELL-BORING AT RICHMOND, SURREY. 781 
of the Jurassic species Peronella mamilli ifera, Lamx., sp., and P. tenuis, 
Hinde. By its simple form and small size this species is “distinguished 
from others of this genus. 
Distribution. Jurassic: Richmond, Surrey, 1205 feet beneath the 
surface. | 
Brastinta cristata, Hinde, n. sp. Plate XXXYV. figs. 3, 3a, 6. 
Sponges small, sessile, hemispherical or conical in form, the 
convex upper surface furnished with a series of ridges or crests, 
some of which extend from the central portion of the summit to 
the basal margin, whilst smaller and shorter ridges are intercalated 
between the larger ; the base is usually concave and is formed of a 
compact wrinkled dermal layer with sharply defined margins. ‘The 
largest specimen measures 6°5 millim. in height by 4 millim. in 
width, and a small individual is only 3 millim. in height and the 
same in width. 
No central aperture or canals are present, and the upper surface 
only exhibits minute irregular apertures bounded by the fibres. In 
a horizontal transparent section the fibres appear as narrow 
labyrinthine bands, from °05 to -12 millim. in thickness, mainly 
composed of three-rayed spicules, the rays of which, in some cases, 
are nearly as wide as the fibre itself. Owing to the crystallization 
of the fibres, no trace of the smaller spicules, which probably 
surrounded the larger, can be distinguished ; on the dermal layer of 
the basal portion indications of three-rayed spicules can be seen 
with a favourable light. 
Four examples of this species were met with in the collection. 
In the largest and best-preserved the surface-ridges project strongly 
and sharply, so as to present a superficial resemblance to the septa 
of a coral, and the object itself calls to mind the small-ridged Polyzoa 
of the genus Defrancia, Bronn. Inthe smaller examples the surface- 
ridges are less regular and not so definite as in the larger form. 
This species is much smaller than Blastinia costata, Goldf., sp., 
and is further distinguished by the less regular arrangement of the 
surface-ridges and the concave form of the base. I have not had 
an opportunity of examining the minute structure of Goldfuss’s 
species, and cannot therefore make a comparison of this feature. It 
is interesting to note that the type of Blastinia costata is from the 
middle beds of the Jura-Kalk at Streitberg. 
Distribution. Jurassic : Richmond, Surrey, 1205 feet beneath the 
surface. 
Buastinia Premma, Hinde, n.sp. Plate XXXV. figs. 4, 4a. 
Sponges minute, sessile, depressed-conical in form, the upper 
surface smooth or with incipient ridges, the base concave, covered 
with a compact dermal layer. An average specimen is 3°5 millim. 
in width by 2:7 millim. in height. The upper surface exhibits 
circular and irregular apertures bounded by the fibres. 
In a transparent section the fibres appear as closely arranged 
