cRagin.] DESCRIPTIONS OF SPECIES. 45 
in advance of the beaks as does the anterior margin of the valve 
itself, its byssal sinus angular or subangular; surface of both valves 
ornamented with numerous fine, closely set, rounded to flattened, 
radial, linear costella?, separated by narrower, serially punctate, 
stria-form grooves, and crossed by concentric growth lines, of which 
some at irregular intervals are more or less strongly imbricated; 
punctations commonly approaching the form of a circumflex accent, 
sometimes appearing dot-like, very closely ranked. 
Measurements. — Height, 39 mm.; length, 34 mm.; breadth, 10 mm. 
(right valve 3, left 7). 
Occurrence. — About 50 specimens were collected, in the Malone 
Hills, H miles east of Malone station, the species ranging nearly 
throughout the fossiliferous Theta there exposed; in foothills about 
1 and 2 miles a little south of east from Finlay station; at a point 
about 2 miles west of Malone station; about three-quarters of a 
mile farther south (all of the four last-named localities representing 
the same or nearly the same horizon. No. 13 of Doctor Stanton's 
Malone Mountain section) ; and at the anticline in the east slope of 
Malone Mountain, nearly a mile north of its southern end. 
Before obtaining a copy of Felix and Lenk's Beitriige zur Geologie 
und Palaeontologie der Republik Mexico I had characterized and 
named in manuscript the above- described common Malone fossil, giv- 
ing it the specific name insutus, in allusion to the peculiar stitched 
appearance of the seams between the ribs. Its ornamentation closely 
resembles that of the Lima comatulieosta, described in that work, 
from the upper Jurassic of Mexico. It differs, however, in several 
respects from that form, as described and figured by Doctor Felix." 
It is provided with ample ears, of which the anterior is several times 
the larger; it is inequivalve; its beaks, instead of being rounded, as 
described and figured by Doctor Felix in his Lima comatulieosta, 
are, when perfectly preserved, rather pointed; and, finally, its outline 
is less obliquely or anteriorly elongated, sometimes even approaching 
in the body of the valves an equilateral or circular outline with a 
pyramidal summit, though usually rather oblique and somewhat 
•elevated. 
The break possibly indicated at the position for an ear in fig. 5 
(loc. cit.) of Lima comatulieosta, the apparent identity of the costal 
and intercostal ornamentation of the Malone Pecten with that shown 
in figs. 1, la, 3, 3a of the Cerro de Titania shell, and the fact that, 
unless the Pecten insutus be it, the LAma comatulieosta is not known 
from the Malone district, while its appearance there might reasonably 
be expected (since at least two b of the seven lamellibranchs described 
by Doctor Felix from the Upper Jurassic of the Cerro de Titania 
" Beitriige, etc., in ralaeontographiea, vol. 37, p. 178, PI. XXVII, figs. 1, la, 3, 3a, 5. 
6 Exogyra subplicifera and Gryphoea mexicana. 
