490 if, Stiffen Netdon — Fo&sifo from Singapore* 
Arcta fip, (PI. XXV. Fig. 14.) 
Shell narrow, elongate; hinge-line horizontal Anri pared Ud with 
ventral border; umbo depressed, anterior, oldiqnc ; cariuated 
obliquely ami obtusely from itmboiml region to pnstcro-ventral 
margin ; anterior end rounded, posterior truncated. and area 
depressed; sculpture consisting of very obscure concentric line* turns 
without evidence of radial strife, 
jHmc»sionn .—Length 20, height Biutn. 
This description applies to a natural east of a right valve 
embedded in the rook showing the external surface. Narrow 
forms ofArca are fairly-connoon in Jurassic deposits, but they are 
invariably ornamented with radial strintion j as mi such sculpture 
exists in the Singapore fossil it may he inferred that tiunft was ever 
present, although it is possible that the counterpart, which doe# 
not appear to have been preserved* might have yielded a better 
interpretation of the original surface structure. 
Collector^ —Sir. J. Ii. Scrivener. 
Gkhvii.ua IlAwmctn, sp. mv. (PI. XXV, Fig. 4.) 
Shell lanceolate, subeylindriwri, curved at ventral margin, 
moderately convex at carina; anterior area, shortest, with an 
Acuta cuneiform termination, narrow and produced posteriorly; 
umbo mil region terminal; dorsal urea, constituting a long narrow 
Obliquely striated depression, entirely bordered within by an obtuse 
Carina, and above by an obscure lengthened hings-Iine; growth* 
lines slightly impressed. 
Di'mmiiojis.“Length 54, height 12 mm. 
This interesting specimen consists of a natural cast and counter* 
part, showing external surface of » left valve, which resembles in 
many of its ohumoteni some Jurassic forma of the genus, such as 
G. nuuiAfrV, DcHhmgchiimpN, from the Bathouian of Britain and 
Europe, or G, tiento, J. de 0. Sowcrby, 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. Hamtacb. 
Yqlskua of, ooiiPHBSSA, Goldfuss. (PI. XXV, Fig. 5.) 
Mytilru cotapreuui, GqldftiKs ; retrpfafcCi tJcirfijinijr, 183?, ml. ii, nl. %- It, 
p. 178. Monk & Lrixtt: Mon. Pub Sac. (Unat Oulite MaUiueia* pari 2.), 
1853, pi. ir, tig. 7, 
In general contour and flatness this shell is closely related to 
Mytilua comprexma of Goldfnsfi, originally described from Hanover 
and the Stonesdeld Slate, The principal distinction appears to ba 
in the concentric li neat ion a, which are fewer and more distant in the 
Singapore fossils, ail hough Rome obscure cnee Are traceable between 
the more important strise, especially on the lateral areas. The ujnbo 
is not terminal as in 31ylilut, so that this form fa recognized as a true 
Voltella (= Modiula). The specimen shows an external view of 
a left valve embedded in matrix. 
Bimetmaut .-^Length 20, height (maximum) 10mm. 
CvUector.— Mr. J. 11, Sc rive nor. 
