Vol. 65.] THE GENUS LOXONEMA. 223 



suture, concave below that and then convex. Sutures very slightly 

 inclined. Lines of growth strong, curving very obliquely backward 

 above and less strongly forward below ; sinus situated above the 

 middle of the whorl. 



Remarks and resemblances. — Two shells now registered 

 as Nos. 21061 & 21062, in the Museum of Practical Geology, repre- 

 senting distinct species, are placed together on the same tablet with 

 the name Loxonema striatissimum. The name was probably given 

 by Salter in MS., and was published by Huxley & Etheridge in 

 1865. 1 Later the genus was changed to Murchisonia, and the 

 specimens were entered as M. striatissima in the Catal. Cambr. & 

 Sil. Poss. Mus. Pract. Geol. 1878, p. 55. No descriptions were 

 given at either of these dates. In 1897 Mr. P. R. Cowper Reed'- 

 described a species under the name of L. striatissimum, considering 

 it conspecific with one of these specimens in the Museum of 

 Practical Geology, but he did not state which. Through his courtesy 

 I have been enabled to examine his holotype. It appears to me 

 quite distinct from either : it is much larger, and the contour is 

 different. As, however, it is merely (with the exception of a 

 small portion of the base) an internal mould, it is impossible to 

 make an accurate comparison. Considering the above circum- 

 stances, it seems advisable to drop the name striatissima for the 

 shells numbered 21061 & 21062 respectively, and to consider each 

 a new species. I suggest calling the former Loxonema reedi and 

 regard it as the holotype. There is no doubt as to its being Loxo- 

 nema and not Murchisonia, as the characteristic form and lines of 

 growth are well preserved. A fragment consisting of about two 

 and a half whorls from the same locality (namely, the Chair of 

 Kildare), in the Sedgwick Museum, may be this species ; but it is 

 larger, slightly compressed obliquely, and the surface is worn :. 

 it cannot, therefore, be identified with certainty. L. reedi some- 

 what resembles L. ledburiense (p. 219) in being much elongated, and 

 in the high position of the sinus ; but it is much smaller, the whorls 

 are more excavated above, and the obliquity of the lines of growth 

 is not so great, more especially below. In its small size, it is like 

 L. dalecarlicum, Lindstr. ; but it is distinguished therefrom by having 

 the whorls concave above instead of evenly convex. 



Dimensions. — The length of the holotype is 21 millimetres. 

 The specimen is so much embedded in the matrix that it is im- 

 possible to ascertain its exact width. 



Locality and horizon. — Chair of Kildare, in rocks of Upper 

 Bala age (Cowper Reed). 



Subgenus Rhabdostkopha, Donald. 



Bhabdostropha, Donald, 1905, Quart. Journ. Geol. Soc. vol. lxi, pp. 564-65. 



Diagnosis. — Shell much elongated, composed of numerous, 



i Catal. Coll. Foss. Mus. Pract. Geol. p. 12. 



2 Quart. Journ. Geol. Soc. vol. liii, p. 78 & pi. vi, fig. 6. 



