CepHatopopa. | DEVONIAN MOLLUSCA. 405 
Neither of the specimens which seem to have occurred to Prof. Phillips, nor the one which I have myself 
seen, is in a fit state of preservation to afford even an approximation to the true characters. 
The specimen in the collection is a fragment about six and half inches long, imperfect at each end, one 
inch eight lines in diameter at the large end, and with rather an abruptly unciform arch towards the small end, 
the septa varying from little more to little less than two lines apart. 
Position and Locality —In reddish calcareous Devonian shales of Torquay. 
CYRTOCERAS RETICULATUM (Phill. ) 
Ref —Phill. Pal. Foss. f, 224. 
Sp. Ch.—Involute, section of the whorls nearly circular, but the periphery more arched than the inner edge ; 
sides marked with very strong, obtusely-rounded, undefined wrinkles, rather more than their width apart, two 
interspaces about equalling the diameter of the volution, at six lines in diameter, the wrinkles becoming 
gradually almost obsolete as they pass across the periphery, ending more abruptly at the flanks of the inner 
face, which they do not cross; entire surface marked with longitudinal, thread-like, equal strie, twice their 
thickness apart, six in the space of two lines, reticulated by very fine sharp transverse strize; septa moderate, 
concave; siphon marginal; a fragment of an arched whorl seven lines in antero-posterior diameter, diminishes 
to five lines in antero-postero diameter in a length of one and half inches ; greatest width seven lines. 
Position and Locality—Devonian limestone of Newton Bushel. 
CYRTOCERAS SUBORNATUM (M/°Coy). Pl. 2. A, fig. 14. 
Ref —M°Coy, Ann. Nat. Hist. 2nd Series, Vol. VIII. 
Sp. Ch.—Gradually arched, involute; section of the whorls a regular transverse ellipse, the shorter axis 
in the plane of involution ; tapering at the rate of five lines in two inches, from a diameter of one inch five lines ; 
periphery broadly arched, inner face rather more convex; sides elliptically rounded, bearing an obscure spiral 
ridge on each side along the most prominent part, bearing a row of large, obtuse, conical tubercles, nearly twice 
their diameter apart ; on each side of this principal row of tubercles is a secondary obscure row, about half as 
far from the principal ridge as the tubercles of it are from each other; the outer of these rows most distinct, tlie 
inner nearly obsolete ; these three sets of tubercles are connected by very obscure transverse wrinkles which do 
not extend beyond them across either the inner aspect or periphery ; entire surface crossed by very minute, 
imbricating, waving lines of growth, having a very obtusely-angular backward sinus in the middle of the 
periphery, all crossed by very faint longitudinal folds half a line apart, never assuming the prominence of strize 
or ridges; siphon close to the outer margin. Proportional length of section compared to the width ©. 
This beautiful species is most closely allied in form, size, septa, siphon, and striation, to the C. ornatum 
Gold, as figured by d’Archiac and de Verneuil in the Geol. Trans. Vol. VI. t. 28. f. 5, but is rather less rapidly 
curved, and is completely distinguished by the two or three rows of tubercles being very small and entirely 
confined to the sides, leaving the broad periphery completely free of them. 
Position and Locality.— One fragment three inches long from the Devonian limestone of Plymouth. 
Explanation of Figures.—P|, 2. A. fig. 14, natural size, side view, shewing the three rows of tubercles on 
the sides, and the convexity of the septum at smaller end; fig. 14 a, end view of septum, shewing the position of 
siphon at outer margin. 
Genus. ORTHOCERAS. See page 312. 
ORTHOCERAS STRIATUM (S07.) 
Ref. = Orthoceratites striatus Sow. Min. Con. t. 58. Orthoceras species Sow. Geol. Trans. 2nd Series, Vol. V. 
t. 54. f. 21% =O. tenwistriatus Miinst. Beitriige, Heft. 3. t. 20. f. 4. 
Sp. Ch.—FElongate, conic, very slowly tapering (at an angle of about 9°), slightly compressed ; section 
broad-oval, its width ;; of its length; siphuncle large, about half its diameter; eccentric towards one of its 
