Paleozoic Phyllopoda, ete. 203 
third border (d), which swells out with a broad curve to meet the 
other sloping edge (6) first mentioned. Near the angle (e), between 
the last mentioned and the straight edge, is a round spot, which 
may have been the base of a large prickle or outstanding spine; and 
the surface of the other (narrower) part of the test is besprinkled 
with minute spots, which may have been the bases of small prickles. 
- If looked at as being possibly the valve of a Ceratiocaris, it does. 
not agree in outline and features with any known species, and its 
markings are foreign to that genus. The only approximate analogue 
is the somewhat apocryphal figures or diagrams in “ Siluria,” 1857, 
p. 262, Fossils (65), 1 and 2, with which we cannot as yet collate- 
exactly any specimens. 
Another, but even more doubtful analogue, may be perhaps seen 
in the outline of A. 8. Packard’s Cryptozoé problematica, Proceed. 
Amer. Phil. Soc. vol. xxiii. 1886, p. 380, fig. 1. 
If our specimen be placed with the slope, e, 6, wpwards, it might 
possibly be regarded as the right valve of an Aptychopsis were it not 
that the lower edge, c, would form one side of a posterior notch 
strange to that genus, and the surface-marks would also be abnormal. 
Some such posterior notch exists in Dipterocaris and its allies; 
but the moieties or ale of their carapaces not being sutured, 
coalesce at the junction. 
We must therefore leave this interesting, but enigmatical, fossil 
to some future investigation before we can decide upon its characters. 
and alliance. 
DESCRIPTION OF PLATE X. 
Fic. 1. Peltocaris Salteriana, sp. nov., a, natural size; 6, magnified 3 diameters. 
», 2. Fragment of a Conularia, a, nat. size; 6, magn. 3 diam. 
», 8. Dipterocaris Etheridgei, T. R. J. and H. W., nat. size. 
», 4. Mytiloid shell, @, nat. size; >, magn. 2 diam. ; ¢, ornament, magn. 15 diam. 
», 0. Mytiloid shell, natural size. 
», 6. Fragment of a Phyllocarid ? a, nat. size; 6, ornament, magn. 15 diam. 
», 1. Aptychopsis Williamsii, sp. nov. Left valve; nat. size. 
», 8. Ceratiocaris insperata, Salter. Two counterparts, @ ana c¢, nat. size; 0, orna- 
ment on one of the stylets, magn. 3 diam. 
», 9. Ceratiocaris insperata, Salter. Impression; nat. size. 
