CERATIOCARID^. 
CERATIOC ARTS, McCoy. 1849. 
Ceeatiocaris longicauda. 
PLATE XXXI, FIG. 1. 
Cemtiocans longicaudus, Hall. Sixteenth Kept. N. Y. State Cab. Nat. Hist., p. 73, pi. i, tig-. 7 (not figs. 4, 
5 and 6). 1863. 
(Jeratiocaris longicaudus, Packard. Twelfth Ann. Kept. U. S. ^Geol. Surv., Monog. N. Amer. Phyllopod 
Crust., p. 450. 1883. 
Co-atiocaris (?) longicaudus, Jones and Woodward. Notes on Phyllopod. Crust., referable to the genus Echi- 
nocaris, etc., Geol. Mag., Dec. iii, vol. i. No. 9, p. 1. 1884. 
Cemtiocaris longicaudus, Etheridge, Woodward and Jones. Third Kept. Com. on Fossil Phyllopoda 
of the Palieozoic Rocks, p. 35. 1885. 
Not Ceratiocaris longicaudus, Clarke. Bull. U. S. Geol. Surv., No. 16, Higher Devonian Faunas of Ontario 
county, N. Y., p. 20. 1885. 
The original of this species is a very tenuous impression of the last two 
abdominal somites and two caudal spines, one of which may be the telson. Of 
the somites the penultimate is broad and sub-quadrate, slightly longer than wide; 
the ultimate much narrower and more elongate, being twice as long as wide. 
The caudal plate is not distinguishable; of the two spines, one, which is un¬ 
broken, is as long as the two somites. The entire length of the fragment is 
26 mm.; the first of the somites measures 5 mm. in length and 4.5 mm. in 
width; the second 7.5 mm. in length and 3.7 mm. in width, and the longer of 
the caudal spines has a length of 12.5 mm. The specimen has been so flat¬ 
tened in the shale that superficial markings are not discernible. But a single 
example of this species has been observed, and this is from the black slaty shale 
