50 Professor T. R. Jones — On a Malayan Estheriella. 



II. — Note on a Teiassic Estheriella from the Malay Peninsula. 



By Professor T. Rupert Jones, F.R.S., F.G.S. 



(PLATE II.) 



Introdiuciion. 



NUMEROUS specimens (having the general aspect of Estheria) 

 lie on the bed-planes of a bluish, slight!}' micaceous, non- 

 calcareous shale from the " Shale and Sandstone Series " of the 

 Federated Malay States. The valves lie flatwise in the strata, 

 either singly or in still connected pairs ; and are not so much 

 compressed but that they show the concavity of the insides, and 

 the convexity and special features of the outsides. There are 

 many examples of valves in different stages of growth, but a 

 striking similarity of character indicates that all belong to one 

 species. The shell itself is absent, but hollow moulds of one 

 valve and solid casts of the other supply material for defining its 

 character. No other organisms have been recognized in the shale. 



Description of the Species. 



The valves (see PL II, Figs. 1-3) are broadly subovate, nearly 

 semicircular, short, and broad or oval-oblong with rounded ends. 

 The anterior extremity has the bolder curvature. The dorsal border 

 is nearly straight ; ventral border boldly curved. The umbo is 

 towards the anterior end of the dorsal border, at about one-third 

 of the length of the valve. Behind the umbo the border gently 

 slopes to the postero-dorsal angle, and has a distinct but narrow 

 marginal fold. The valve is of the same shape as fig. 19 in pi. iii, 

 "Monograph of Fossil Estherice," Pah Soc, 1862, p. 103, but with 

 a more definite postero-dorsal angle ; the short form, var. sub- 

 qiiadrata, of the Wealden Estheria elliptica (4^ mm. long). 



Many concentric parallel ribs or wriniiles, such as are observable 

 in known Estherice, are shown by these Malayan specimens, both 

 on the casts of the outsides and in tliose of the insides of the valves. 

 In some respects, howevei', these concentrics of the Malayan species 

 differ from those of almost all other Estherians, namely, (1) in 

 being less ridge-like, broader, and more convex individually; 

 (2) in having numerous small, subsidiary, parallel, raised lines, 

 intercalated on their surfaces and in their interspaces ; and (3) by 

 being crossed with a radial ornament. The main concentrics or 

 wrinkles are about fifteen in number, and are frequently seen to be 

 pushed up into ridges near the umbo, as in specimen ' A,' PI. II, 

 Fig. 2, corresponding in its raised concentrics to the furrows in 

 specimen ' B,' PI. II, Fig. 1. At the umbo they are squeezed 

 together, and indeed crushed down ; but they are broader and 

 rounded elsewhere. Throughout they ai'e marked with the 

 supplementary riblets (5 or 6) both on the regular costaa and others 

 between them where there is interstitial space enough. 



The Malayan specimens are characterized by having twenty-four 

 and more delicate, close-set, parallel, linear fuiTows radiating from 

 the umbo to the ventral edge of the valve. In some cases they are 



