CepHALopopa. | DEVONIAN MOLLUSCA. 403 
CuiyMentra Partisont (M°Coy). Pl. 2. A. fig. 11. 
Ref—M Coy, Ann. Nat. Hist. 2nd Series, Vol. VIII. 
Sp. Ch.—Discoid, compressed, of about five whorls, rather more than one-third of each being concealed by 
the preceding turn ; section of the whorls semielliptical, greatest thickness near the edge of the umbilicus, which 
is considerably wider than the last whorl; sides very slightly convex, gradually converging to the obtusely- 
rounded periphery, to which there is often superadded a very fine, thread-like, mesial keel, and two lateral ones ; 
surface finely striated transversely ; siphon large, close to the inner margin; septa about one-third the width of 
the side apart, with the middle portion nearly transverse; the edges, after about the middle of the side, 
arching backwards and then forwards again to the edge of the umbilicus, forming an obtusely rounded first 
lateral lobe, which extends backwards about half the space between the septa further than the middle portion. 
Diameter nine lines, proportional diameter of umbilicus 4, of last whorl =, width of mouth =. 
This species belongs to that very restricted first group of Clymenia according to Mimster, in which the 
edges of the septa are only slightly arched ; it is most nearly allied to the C. compressa Miinster, from which 
however, on comparing with authentic specimens, I find it differs by the great size of the umbilicus, which in 
that species is much less than the last whorl, forming scarcely ;;; of the entire diameter. The septa differ from all 
of this group in the greater forward curvature of the umbilical end of the edge of the septa, thus forming a 
rounded lobe, remarkably close to the umbilical edge, from which the edge of the septum passes with very little 
curvature across the outer half of the sides and periphery, forming no other inflections as in the other allied 
forms. This flexion forward to the umbilicus distinguishes this part very strongly from C. levigata, which 
also has very much more numerous whorls and larger umbilicus. I have much pleasure in dedicating this 
species to Mr Pattison of Launceston, to whose labours in collecting, I believe, is due the discovery of nearly 
all the British specimens of Clymenia. 
Position and Locality—Rare in the Devonian limestone of S. Petherwin. 
Explanation of Figures.—P\. 2. A, fig. 11, natural size ; fig. 11 a, view of mouth, shewing the siphon at 
inner edge; fig. 11 0, line of septum. 
CLYMENIA QUADRIFERA (JM/‘Coy). Pl. 2. A. fig. 13. 
Ref—M “Coy, Ann. Nat. Hist. 2nd Series, Vol. VIII. 
Sp. Ch.—Discoid, compressed, nearly two-thirds of the whorls concealed; whorls about four and half, 
crossed by very minute sigmoid strie; periphery narrow, obtusely rounded; septa with the middle portion 
crossing the periphery very broad, and with a slight forward curvature ; jirst sinus small, oblique, very obtusely 
rounded ; first Jobe nearly in the middle of the side, nearly square, slightly rhomboidal, length and width about 
equal, truncated at the broad extremity—the angle next the umbilicus rather more obtuse, and the other slightly 
more acute than a right angle, sides subparallel ; second sinus slightly higher than the first, extending with 
searcely any curvature to the umbilicus, its width double that of the lateral lobe, which is placed nearly in the 
54 
middle of the side. Diameter one inch three lines, proportional diameter of last whorl ;{,, width of mouth at 
edge of umbilicus ;;,, width of periphery about ;;. 
This species is easily distinguished from all others by the remarkably defined, nearly square form of the 
lateral lobe. It is most allied to the Clymenia striata (Miinster), from which it is distinguished by the very 
obtusely rounded, obscurely defined first sinus, and the regular, almost square-formed lobe, and the scarcely 
curved margin of the second sinus. The cast of that species is also marked by sigmoidal ridges, of which there 
is not the slightest trace on the second species. I have seen traces both of the evanescent thread-like middle 
and lateral keels, occasionally seen on the other species. 
Position and Locality.—Very rare in the limestone of S. Petherwin. 
Explanation of Figures—PI. 2. A. fig. 13, natural size; fig. 13 a, line of septum; fig. 13 4, portion of 
periphery. 
3 F2 
