F. R. Cowper Reed — Fossils from Haverfordwest. 495 



Locality and Horizon. — Slade Beds : roadside 110 yards west 

 of St. Martin's Cemetery ; (variety) Eedhill Stage, Prendergast 

 Mill Lane. 



Eemakks. — This shell has a very compressed form, and its 

 subquadrate shape and subauriculate appearance give it a con- 

 siderable similarity to Nucula deltoidea, Phillips.^ But the latter is 

 less obliquely truncated behind, the umbonal ridge is less sharply 

 marked, and the teeth appear to be more numerous. Ulrich's 

 Ct. CalvinP is apparently more allied. The Eedhill specimens are 

 rather more ovate than those from the Slade Beds, and have the 

 teeth generally better preserved. 



Ctenodonta subscitula, sp. nov. (PL XXIV, Figs. 13, 13a.) 



Description. — Shell elongate-ovate, about twice as long as high, 

 highest at beaks, narrowed posteriorly, strongly convex, most so 

 about middle, somewhat compressed behind. Anterior end broadly 

 rounded, excavated above in front of beaks ; posterior end produced, 

 subacutely pointed, very obliquely truncated above ; inferior margin 

 moderately convex. Hinge-line gently arcuate, with series of about 

 22 small transverse, slightly oblique teeth in front of beaks, 

 increasing somewhat in size towards the front and extending from 

 beaks to anterior end of shell ; post-umbonal series of teeth meeting 

 anterior series at very obtuse angle, but continuous with it and 

 consisting of 9-11 larger transverse teeth increasing rapidly in size 

 posteriorly and successively becoming more obliquely inclined. 

 Beaks prominent, incurved, rising above hinge-line, scarcely bent 

 backwards, situated at about one-third the length of the shell from 

 anterior end. Surface of valves convex, with strong, subangular, 

 curved, diagonal ridge running back from beak to upper posterior 

 angle, limiting a more or less excavated cardinal slope inclined at 

 nearly a right angle to the general convex surface of the valve. 

 Surface of shell marked with regular, equidistant, rather strong, 

 concentric strise. 



Dimensions. 



I. II. 



Length 16"5 ... 13'5mm. 



Height 9-0 ... 7-0 mm. 



Horizon anb Locality. — Eedhill Beds : Prendergast Place 

 and Lane. 



Eemarks. — The characters of the dental series combined with the 

 shape and general features of the shell distinguish it from the other 

 numerous species of Ctenodonta found in the Eedhill and Slade Beds, 

 and I am not acquainted with any described species which can be 



1 Phillips: Mem. Geol. Surv., vol. ii, pt. 1, p. 366, pi. xxii, fig. 5. 



2 Ulrich: op. cit., p. 596, pi. xlii, figs. 61-64. 



