490 li. Bullen Neuion — Fossils from Singapore. 



Arca sp. (PI. XXV, Fig. U.) 



Sliell narrow, elongate; liinge-line horizontal and parallel with 

 ventral border ; umbo depressed, anterior, oblique ; carinated 

 obliquely and obtusely fioni unibonal region to postero - ventral 

 margin ; anterior end rounded, posterior truncated, and area 

 depressed ; sculpture consisting of very obscure concentric lineations 

 without evidence of radial strije. 



Diineiisions. — Lenj'th 20, height 8 mm. 



This description applies to a natural cast of a right valve 

 embedded in the rock showing the external surface. Narrow 

 forms of Arca are fairly common in Jurassic deposits, but they are 

 invariably ornamented with radial striation ; as no such sculpture 

 exists in the Singapore fossil it may be inferred that none was ever 

 present, although it is possible that the counterpart, which does 

 not appear to have been preserved, might have yielded a better 

 interpretation of the original surface structure. 



Collector. — Mr. J. B. Scrivenor. 



Gkkvillia Hanitsohi, sp. nov. (PI. XXV, Fig. 4.) 



Shell lanceolate, subcylindrical, curved at ventral margin, 

 moderately convex at carina; anterior area, shortest, with an 

 acute cuneiform termination, narrow and produced posteriorly; 

 umbonal region terminal ; dorsal area, constituting a long narrow 

 obliquely striated depression, entirely bordered within by an obtuse 

 carina, and above by an obscure lengthened hinge-line ; growth- 

 lines slightly impressed. 



Dimeimons. — Length 54, height 12 mm. 



This interesting specimen consists of a natural cast and counter- 

 part, showing external surface of a left valve, which resembles in 

 many of its characters some Jurassic forms of the genus, such as 

 G. monotis, Deslongchamps, from the Bathonian of Britain and 

 Europe, or 6. acuta, J. de C. Sowerby, of Bajocian age. From the 

 former it appears to differ in its lesser convexity and longer hinge- 

 line, and from the latter in its less oblique and more lengthy 

 hinge area. 



Collector. — Dr. Hanitsch. 



VOLSKLLA Cf. COMPRKSSA, GoldfuSS. (PI. XXV, Fig. 5.) 



Mytilus compressus, Golclfuss : PctreliU'ta Gerniania\ 1837, vol. ii, pi. cxxxi, tig. 11, 

 p. 178. Morris & Lycett : Mon. Pal. Soc. (Great Oolite MoUusca, part 2), 

 1853, pi. iv, %. 7, p. 40. 



In general contour and flatness this shell is closely related to 

 Mydlits oo»jp?-e.s6'ti8 of Goldfuss, originally described from Hanover 

 and the Stonesfield Slate. The principal distinction appears to be 

 in the concentric lineations, which are fewer and more distant in the 

 Singapore fossils, although some obscure ones are traceable between 

 the more important strife, especially on the lateral areas. The umbo 

 is not terminal as in Jlytiliis, so that this form is recognized as a true 

 Volsella (= Modiolu). The specinjen shows an external view of 

 a left valve embedded in matrix. 



Dimensions. — Length 20, height (maximum) 10 mm. 



Collector. — Mr. J. B. Scrivenor. 



