9 
ON THE FOSSIL PHYLLOPODA OF THE PALEOZOIC ROCKS. 361 
/ 
E. socialis is a very small form, belonging to the same group as Whit- 
field’s species from New York State. It measures 18 x10 mm. ; abdo- 
men, 6 mm.; telson, 6 mm. 
Elymocaris has its valves plainer and more oblong than those of 
Bichinocaris. The long straight dorsal edge and elliptically curved 
ventral (deeper behind than in front) give a semi-ovate outline. The 
posterior is truncate, with a hollow curve just below the postero-dorsal 
angle. Ocular tubercle distinct, but the other cephalothoracic nodes are 
less developed than in Hehinocaris, and occupy the angular anterior third 
of the valve. The abdomen preserved in fig. 1, pl. 2, shows a penultimate 
and an ultimate segment (the latter apparently split longitudinally), and 
a trifid appendage of a stout short telson and two stylets almost as broad 
and quite as long, ‘crenuiated along their inner margins for the attach- 
ment of fimbria,’ as in Dithyrocaris Neptunt, Hall, and D. tricornis, Scouler. 
This set of stout small caudal spines and segments will doubtless prove 
very useful in comparing other but less distinct fossil appendages. 
Carapace-valve, 23 x10 mm. ; two segments, 10 mm.; telson, 9 mm. 
Tropidocaris has semielliptical valves (25 x12 mm. and 37 x14 mm.), 
very similar in outline to those of Hlymocaris, but ornamented with 2—7 
longitudinal, interrupted, raised, parallel ridges (somewhat analogous to 
those on some varieties of Kirkbya permiana and K. euglypha, but more 
especially to those on some of the species of Dithyrocaris). Delicate 
curved striz also on some valves. Optic and other nodes present. 
Abdominal segments small, cylindrical, tapering, not well known. 
34. The Corrocaris of F. B. Meek is a Carboniferous fossil of much 
interest, though of doubtful character in some respects. 
1868. Ceratiocaris? sinuatus, Meek and Worthen. ‘Amer. Journ. Sci.’ vol. xlvi. 
p. 22. 
1873. Ceratiocaris ? sinuatus, M.and W. ‘Geol. Surv. Illinois’ (Geol. and Palzont.), 
p. 540, fig. 5, woodcut. 
Somewhat rhombic-subovate; posterior end truncate and deeply 
sinuous; dorsal margin a depressed arch. From the Coal-measures, 
Grundy County, Illinois. 
1872. Colpocaris (?sub-genus of Ceratiocaris) Bradleyi and elytroides, Meek. 
‘Proceed. Acad. Nat. Sci. Philada.’ vol. xxiv. pp. 332-34. 
1875. Ceratiocaris (Colpocaris) Bradleyi, Meek. ‘ Report Geol. Surv. Ohio,’ vol. ii. 
(Geol. and Palzont.), Part II. ‘ Paleontology,’ p. 318, pl. 18, figs. 6a—6e. 
1875. Ceratiocaris (Colpocaris) elytroides, Meek. Op. cit. p. 319, pl. 18, figs. 5a, 5d. 
These are acute-oval, but one end has a relatively large semicircular 
notch cut into it. The first of these two differs but little, except in the 
relative depth and slight obliquity of semicircular notch in what is 
described as the posterior margin. The surface is minutely reticulate 
(fig. 6c). A large and a small individual are figured; 70x32 mm., and 
24x10 mm. Fig. 6d indicates a set of three caudal spines, and 6e, 
another set not so perfect. These were found associated with the cara- 
pace-valves. Figs. 5a, 5b, is a small species (28 x13 mm.) of a generally 
similar outline; and fig. 5c shows its longitudinal linear ornament. 
These are from the Carboniferous beds of Ohio, U.S. As yet we have no 
knowledge as to the exact relationship of Colpocaris. See also Prof. 
Whitfield’s remarks, ‘ Americ. Journ. Sci.’ vol. xix. 1880, p. 36. 
The other Phyllopodous genera mentioned in our lists, such as Dithyro- 
caris, Hstheria, &c., will be treated of at another opportunity. 
