290 PALEOZOIC PALEONTOLOGY. 
vary considerably in this character, a specimen occasionally being 
observed which has fully as coarse plications as the earlier ones. The 
species varies considerably in size, one of the larger specimens ob- 
served being 18 mm. long by 17 mm. wide, which is considerably 
larger than any which have been seen in the Decker Ferry fauna. 
MERISTELLA LAEVIS (Van.). 
Plate XXXI., Figs. 1-8: 
See, also, p. 317. 
The representatives of this species in the Coeymans limestone 
fauna of New Jersey are all small, it rarely attaining a length of more 
than 10 mm. At the very summit of the formation near Hainesville, 
however, some larger individuals have been observed, one being 16.5 
mm. in length and another 18 mm. They agree in all respects with 
the younger individuals of the species as it occurs in some of the 
higher beds, being smooth, longitudinally subovate shells, with no ~ 
sinus in the pedicle valve’except in the case of the somewhat larger 
individuals already mentioned from the top of the formation. 
NUCLEOSPIRA VENTRICOSA Hall. 
Plate XXX., Kies. 19-22: 
1859. Nucleospira ventricosa Hall, Pal. N. Y., vol. IL, p. 220, pl. 
14, figs. 1 a—n, pl. 28 B, figs. 2-9. 
Description —Shell small, subglobose, usually a little wider than 
long, the valves subequally convex. Pedicle valve with a narrow and 
shallow mesial depression, which becomes faint or almost obsolete on 
the umbo; the beak closely incurved over that of the brachial valve. 
Brachial valve with a median depressed line which is less conspicuous 
than that of the pedicle valve. Surface marked by indistinct, con- 
centric lines of growth; when perfect, covered with minute hair-like 
spines. 
The dimensions of a small, but nearly perfect individual, are: 
length, 6 mm.; width, 6.25 mm.; thickness, 4.25 mm. 
Remarks.—Vhis little species has been observed in the Coeymans 
limestone, only in the upper beds, near Hainesville. 
