EcuinopErMAta. | DEVONIAN RADIATA. HU 
CYATHOCRINUS GEOMETRICUS (Gold.) 
Ref. and Syn.—Gold. Pet. Germ. t. 58. fig. 5. Phill. Pal. Foss. t. 60. f. 41. 
Sp. Ch.—Cup from pelvis to top of Ist secondary radials (scapulze), about eleven lines (large specimen), 
greatest width (at middle of Ist primary radials) one inch three lines, diameter of pelvis ten lines; height 
and width of the primary radials equalling seven lines, or the width slightly exceeding the length, if 
measured directly; secondary radials about six lines wide, and five high, with a deep narrow articular 
notch, for the second joint of the secondary radial series, forming the base of the free rays; interradial 
plate six lines wide, and the same in height; surface of the five primary radial plates, conically protu- 
berant in the middle, the rest flattened; two or three coarse subequal parallel ridges extend from the 
centre of each plate, through the middle of one of its straight sides to the centre of each of the adjoining 
plates. 
Position and Locality —Not uncommon in the Devonian limestone of Newton Bushel. 
9th Ord, CysTipEa. See page 61. 
SPHZERONITES TESSELATUS. (Phill.) 
Ref—Phill. Pal. Foss. t. 59. 
This name has been provisionally given by Prof. Phillips to an irregularly pyriform ‘fossil, of which a 
figure is given by Sir Henry de la Béche, in the “Transactions of the Geological Society of London,” y. 3. t. 20. 
which has been copied by the former into his “ Palzeozoic Fossils.” None of the characters of the genus 
Spheeronites have yet been recognised in it however; and the true genus of the fossil is very doubtful. 
All the specimens are more or less pear-shaped, inflated, and obtusely rounded at one end, tapering nearly 
to a point at the other; the length varies from three to six inches, and the greatest width (about one- 
third from the broad end) is rather less than two-thirds the length; the whole surface seems covered 
with subequal hexagonal, or occasionally heptagonal, calcareous plates, usually one-half or two-thirds of a 
line thick, and about 2 lines in length and width. I have never seen any plates so large as those repre- 
sented in the above-mentioned figure, but they vary slightly in size and shape within short distances, sometimes 
the length, sometimes the width, being a little in excess. On the outer side each plate is raised into an 
obscurely defined rounded tubercle in the middle: the entire of the inner surface is latticed with strong 
vertical, prominent lamellar ridges, coinciding with a vertical line drawn through the centre of each row of 
plates, new ridges being added by intercalation as the width increases; the intervening spaces are crossed 
at regular intervals by less prominent lamellar ridges, at right angles to the strong vertical ones, and also 
coinciding with the centres of the plates—each plate bearing on its imner face a lamellar cruciform projection, 
the vertical branches strongest, and bisecting the upper and lower sides of each plate, and the lateral 
branches reaching the lateral angles; the union of these parts forming the regular reticulating ridges of the 
general interior. 
From the obscure specimens I have seen of the Receptaculites Neptuni, I should say the present fossil 
ought to be referred to that genus, rather than to Sphwronttes, and it is possible they may be specifically 
identical. One of the smallest specimens in the Cambridge collection shews near the broad extremity what 
may be a rounded valvular ovarian rosette, about three lines in diameter, apparently of five pieces, but the 
entire appearance may be deceptive, and requires to be confirmed by other specimens. 
Position and Locality—Common in the Devonian limestone of Plymouth. 
