248 F. R. Coivpar Reed — Salter's Undescribed Species. 



Pleurotomaria ctclonema (Salter). (PL XI, Figs. 1-3.) 



1873. M'urehisonia eyelonema, Salter : Cat. Camb. Sil. Foss. "Woodw. Mus., 



p. 155 {a 848, a 849, a 850). 

 1891. MurcJiisonia eyelonema, Woods: Cat. Type Foss. Woodw. Mus., p. 107. 



There are in all fourteen specimens labelled MurcTiisonia eyelonema 

 by Salter, varying in size from 10 mm. to 36 mm, in length. 

 Several are in an excellent state of preservation, and all come from the 

 Wenlock Limestone of Dudley and belong to the Fletcher Collection. 



DiAaNOSis. — Shell conical, turbinate ; whorls five, ventricose. 

 Apical angle 50°-60°, being smaller in the older and larger 

 individuals. Body- whorl large, equal to half the length of shell or 

 even more. Slit-band a little above middle line of body- whorl, but 

 in other whorls half-way between the suture-lines. Apical surface 

 with distinct swollen band immediately below upper suture-line of 

 each whorl, and with one rounded, prominent, longitudinal keel 

 between this band and the slit-band. Six or seven longitudinal 

 keels below slit-band on body-whorl, of which the uppermost three 

 or four are prominent rounded ridges, usually nearly equal in size, 

 and nearly equidistant. The other three or four longitudinal keels 

 on the body-whorl are on the umbilical surface, and grow 

 successively much narrower, fainter, and less prominent. On the 

 upper whorls the uppermost three longitudinal keels are alone 

 developed in the adult, the number varying from one to three 

 according to age. Slit - band prominent, of moderate width, 

 bordered on each side by narrow ridge. Surface concave, but 

 marked along centre by longitudinal keel, varying in degree of 

 development, but making profile of slit-band very characteristic. 

 Crescents not very numerous, gently arched backwards, but strongly 

 marked, and in some of the smaller individuals sub-lamellar. Apical 

 surface of whorls crossed obliquely by fine sigmoidal thread-like 

 raised lines, at regular distances apart in young individuals but more 

 closely and less regularly packed in adults. Below slit -band the 

 whorls are ornamented by similar transverse lines, but crossing the 

 keels nearly at right angles instead of obliquely. On both sides of 

 the slit-band the lines are sharply bent back. 



Mouth large, subcircular or oval, slightly oblique to axis of shell. 



Measurements. 



Length 



Breadth (across body-whorl) 

 Apical angle 



Kemarks, — This species bears much resemblance to Pleurotomaria 

 laqueata (Lindstrom),^ from the corresponding beds of Gotland, in 

 its general shape, in the distribution and number of the keels, and 

 in the position of the slit-band, but differs in the minute characters 

 of the latter, which is an important point. 



It has the general aspect of PL Lloydi, Sow,, but differs in having 

 only one keel above the slit - band and fewer and larger keels 



^ Lindstrom : op, cit., p. 102, pi. ix, figs. 4-6. 



