302 MRS. JANE LONGSTAFF ON SOME NEW [Sept. 1912^ 



whorls of the spire and above the middle of the body-whorl, lines 

 of growth acutely bent upon it. Ornamentation consisting of very 

 fine spiral striae. Columella but slightly curved. 



Remarks and resemblances. — This form resembles the last 

 to such a degree that I hesitated at first as to whether it should be 

 regarded as a distinct species, or merely as a variety. The shape 

 of the band, hoAvever, appears very different, being narrower and 

 convex, and the lines of growth are more acutely bent upon it ; 

 also the whorls are rather more evenly convex, whereas those of 

 F. hibernica are somewhat quadrangular. It is distinguished from 

 Ptychomplialus ivalciodorensis De Kon.^ by having a higher spire, 

 band not quite so wide, columella nearly straight, and lines of 

 growth more oblique. The holotype (PI. XXIX, fig. 2) and an 

 associated specimen (fig. 1) were in Dr. Foord's collection, Dublin, 

 but they are now in the Munich Museum. They are both re- 

 markable for having the columella fairly well preserved, and fig. 1 

 has the body-whorl near the aperture rather inflated and squeezed 

 into wide folds. 



Dimensions. — The apex of the holotype is broken : the 

 remaining seven whorls = 6-5 centimetres in length and 5*1 cm. in 

 width. The other example (fig. 1) is still larger, having three and 

 a half whorls in a length of 7*2 cm., and its width = 6-25 cm. 



Localitie s. — The holotype and its associate are from St. Doulaghs,. 

 Dublin. A specimen in Trinity College Museum, Dublin, one in 

 the British Museum (Natural History) No. 26255, and perhaps also- 

 an example having merely the upper part of the spire preserved in 

 the Museum of Practical Geology, London, are conspecific, and all 

 come from Kildare. Another individual in the last-named Museum 

 is from Cloonlara (County Clare). A second shell on the tablet, 

 Xo. 26255, is too much worn for identification. 



Horizon. — Lower Carboniferous Limestone. 



^ Genus Motjrlonia De Kon. : Subgenus Trechmannia, nov. 



Diagnosis. — Shell trochoidal. Whorls rapidly increasing, more 

 than three in number, flattened above, with a prominent keel 

 considerably below the middle, which appears a very short distance 

 above the suture on the penultimate whorl ; below the keel the 

 whorls are slightly concavo-convex, and slope rapidly into the 

 sutures. Sutures deep. The ornamentation on the upper part of 

 the whorl consists of strong raised threads, sloping very obliquely 

 backwards along the course of the lines of growth ; these continue 

 to the edge of the keel, below which they run slightly backwards 

 with much less obliquity than those above. A rather wide and 

 deep groove encircles the whorls immediately above the keel, 

 bounded on the upper side by a blunt ridge. Entire surface 

 covered by very fine spiral lines. Contour of the keel concave 

 above and below. Beneath it there is a slighth' grooved band, 

 only seen when the keel is broken, with a fine thread running 



1 Ann. Mus. Roy. Hist. Kai. Belg. vol. riii (1883) p. 38 & pi. xxiv, figs. 2-3. 



