30 SYNOPSIS OF THE CHARACTERS OF THE 



LoxoNEMA BREVis. M'Coy. (PL III. fig. 2). 



Sp. Ch. — Elongate, ovate ; spire obtuse, of five, gradually increasing volutions ; whorls slightly convex, with 

 rather distant, strong, slightly arched, longitudinal ridges, thickest and most prominent below, originating in a 

 small tubercle above ; basal whorl very little larger than the preceding one. 



Differs from the L. rug if era in the short form and less number of whorls, and from the Devonian var. of 

 L. tumida in the flatness of the whorls, and stronger sulci. Length three and a half Unes, width one and a 

 half lines. 



LOXONEMA CONSTRICTA. Mart. SP. 

 Melania constricta. Sow. Min. Con Melania constricta. Phil. Geol. York — Loxonema tenuistriata. Portk. Geol. Rep. 



Sp. Ch. — Smooth, whorls tumid below, constricted above, sutures crenulated. 



The constricted form of the upper part of each whorl, and the strongly plaited sutures, distinguish this spe- 

 cies from its congeners; the latter character, however, is rarely well seen. Captain Portlock's L. tenuistriata 

 does not seem to differ from the ordinary state in which specimens of this species are found. Length two inches 

 six lines, diameter of last whorl nine lines. 



Loxonema impendens. M' Coy. (PI. III. fig. 3). 



Sp. Ch. — Turreted, elongate, smooth; spire of about nine or ten, gradually increasing whorls ; volutions 

 flat above, very tumid, and obtusely rounded below ; sutures plain, very slightly imbricating ; surface smooth. 



This fine shell differs from the L. constricta, in its plain (not crenated) sutures, the sutm-es not being 

 constricted, and the greater prominence of the whorls below; from the L. siilculosa, Phil., in the smooth sur- 

 face, and from the L. suturalis, Phil., in the sutures not being prominent. Length about two inches five lines, 

 diameter of basal whorl one inch. 



The specimen figured was obligingly communicated by Mr. Newenham, of Cork. 



Loxonema POLYGYRA. M'Coy. (PI. III. fig. 1). 



Sp. Ch. — Very elongate, slender; spire of eleven, very convex, gradually increasing whorls, each marked 

 by five strong spiral ridges. 



This beautiful little shell is remarkable for its small size and very attenuate form ; the volutions are more 

 numerous than in the other species. From the L. acicula, Phil., it is known by the greater number of the 

 spiral ridges. Length three lines, diameter half a line. 



Loxonema pulcherrima. M'Coy. (PL VII. fig. 7). 



Sp. Ch. — Very much elongate, volutions numerous, flattened, crossed by sharp sigmoidal sulci, deepest at 

 the upper edge ; mouth twice as long as wide. 



This beautiful species is distinguished from the L. nexilis by the greater curvature and sharpness of the 

 striae ; the volutions are flattened, numerous, their length and breadth about equal. The mouth in the speci- 

 men figured is very perfect. 



Loxonema sulcatula. M'Coy. (PL V. fig. 6), 



Sp. Ch. — Elongate; spire acutely conic, of seven convex whorls, each girt with about ten equal, spiral 

 sulci. 



This shell is distinguished by the great number of Its spiral sulci. Length five lines and a half; diame- 

 ter of basal whorl two lines and a half; height of basal whorl two lines. 



