32 
BULLETIN OF THE LABORATORIES 
extremely arcuate, the beak recurved upon itself so that the hinge line 
is nearly opposite the centre of the back of the shell ; hinge line shorter 
than the width of the shell ; cardinal extremities produced into small 
angular ears. Surface marked by strong radiating costae, which bifur- 
cate upon the umbo and below, and sometimes coalesce toward the 
base of the shell ; entire surface covered by fine undulating concentric 
striae, and, in the upper part, a few strong wrinkles, which are con- 
spicuous on the ears and umbo. A few marks of the bases of spines 
are noticed, but they appear to have been irregularly distributed.” 
This species is P. semireticulatus in miniature. Our specimens 
differ from Hall’s figures chiefly in the greater irregularity of the striae, 
in this respect, however,' agreeing with his description. 
Length 17 mm; width about 15 mm; hinge 14 mm. Near congl. 
II, Granville and Newark. 
Productus flemiivgi, var. hindln^tonensis . H. 
(Plate III, Fig. 20 [and 22?]) 
A few specimens, apparently from the upper division of the Wa- 
verly, resemble very closely this species. The occurrence of a Bur- 
lington species in this horizon is certainly suggestive. 
Productus {Productella) shinnardianus , H. 
Plate VII, Fig. 18; Plate VI, Fig 16?) 
(= Productus subaculeatus, Murch.) 
Pj'odiictus subaculeatus, has been identified by Hall, from the Cor- 
niferous He says : 
“ I have been unable to identify it with any species in the Ham- 
ilton and Chemung groups of New York, though the resembling those 
which I have placed under P. shumardiana. x\ larger collection of 
specimens may possibly show a passage from one to the other.” 
Productus shumardianus is doubtless identical with P. spinulicos- 
tus, H., P. concentricus, H; and P. pyxidata, H., while P. lach 7 ymosa 
is perhaps less closely allied, though a member of the same series. 
