﻿Vol. 6 I.] TERTIARY POSS1LS OF SOMALILAND. 1G7 



of Ostrea orbicularis. It represents a fragment of a slightly-convex 

 valve, showing a shallow ligamental area with a straight horizontal 

 inner margin. The ribs are prominent and bifurcating, the channels 

 between them being deeply excavated, and so producing a plicated 

 margin. The surface is much worn, consequently there are no 

 traces of an imbricated structure. It resembles very closely J. de 

 C. Sowerby's original figure, as well as Dr. Frauscher's illustrations 

 of examples from districts of the Northern Alps. Dr. Oppenheim 

 regards this species as equivalent to Schafhseutl's Ostrea semi- 

 pectinata, suborbiculata, and abscissa, and unites all three under the 

 first-named species ; but Schafhseutl's figures are so obscure for 

 such a determination, that it is far better to retain Martinsi of 

 A. d'Archiac. It is, however, interesting to know from Dr. Oppen- 

 heim's memoir that this shell is recognized in the Egyptian Eocene ; 

 and the present Somaliland example appears to offer characters of 

 such close relationship as to make it almost certain that it is a 

 second instance of its occurrence in Northern Africa. 



Locality. — Dobar, south of Berbera. 



Collector. — Mrs. Lort-Phillips. 



Mat rix.— The so-called < Dobar Limestone.' [B.M.— L. 14927.] 



Oryphjea Gkegokyi, sp. nov. (PI. XVII, fig. 4 & PI. XXI, 

 figs. 1 & 2.) 



Gryplicea vesiculosa, R. B. Newton in Gregory, Quart. Journ. Geol. Soc. vol. lvi 

 (1900) p. 43; non J. de C. Sowerby. 



Shell small, thin, strongly arched, sides abrupt, subrhomboidal, 

 summit depressed ; growth-lamellse irregular and sinuated at the 

 lateral lobe ; umbonal area incurved ; anterior margin extended 

 at the hinge, and forming a small auricle ; posterior lobe well- 

 defined, expansive and moderately concave externally. 



Dimensions in millimetres. 



Umbono-ventral =27 I Convexity of the left valve . . . = 25 



Antero-posterior , .... =25 | 



This species is founded on external characters of the lower or 

 left valve only, of which there are several examples more or less 

 fragmentary, both in Major Leckie's collection and in that formed by 

 Mr. Parkinson, referred to in Dr. Gregory's paper as a Cenomanian 

 fossil with the name of Gryphcm vesiculosa. The specimen described 

 and figured belongs to this latter collection, being preserved in the 

 British Museum under the registered number L. 12666. 



The present species is related to several Eocene forms of this 

 genus, such as Gr. eversa, Melleville, from France, Gr. laticeps, 

 Schafhteutl, from Kresseuberg, and Gr. Escheri of Mayer-Eymar, which 

 includes Gr. gri/phovicina, S. V. Wood, and Gr. pseudovesicularis, 

 Giimbel, from England, the Northern Alps, and Kressenberg ; but 

 it is well separated by its subrhomboidal form, its strongly-arched 

 central region, the somewhat steep sides, and rather wide but not 

 produced lobe of the posterior area. For synonymy and further 

 particulars of these species reference should be made to an important 



