EUGXATHIDiE. 
339 
dorsal fin being relatively large. Scales in part ornamented with 
radiating series of very fine granulations. 
Form. $ Loc. Lower Kimmeridgian (Lithographic Stone) : Ain, 
France. 
Not represented in the Collection. 
Caturus angustus, Agassiz. 
1844. Caturus angustus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. p. 118. 
1893. Caturus angustus, A. S. Woodward, Ann. Mag. Nat. Hist. [6] 
vol. xii. p. 398, pi. xviii. fig. 1. 
Type. Fish, wanting head ; Worcester Museum. 
An imperfectly defined species, known only by the type specimen, 
which measures 016 from the origin of the dorsal to the fork of the 
caudal fin. Trunk much elongated, the width of the caudal pedicle 
scarcely equalling half the depth of the trunk between the dorsal 
and pelvic fins. The origins of these two fins directly opposed, and 
the dorsal with about 20 rays ; anal fin about as large as the pelvic 
fins, with not less than 12 rays. 
Form, Loc.. Portlandian : Garsington, Oxford. 
Not represented in the Collection. 
Caturus heterurus (Agassiz). 
[Plate IX.] 
1839-44. Pachycormus (P) heterurus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 
p. 113, pi. lviii. a. figs. 4, o. 
Type. Tail; Oxford Museum. 
A robust species of medium size, attaining a length of about 
0'4o. Length of head with opercular apparatus exceeding the 
maximum depth of the trunk and contained about four times in 
the total length of the fish ; depth of caudal pedicle equalling about 
half the maximum depth of the trunk. External head-bones, 
supratemporals, and opercular bones ornamented only in part with 
feeble rugae and tuberculations ; maxillary teeth small, slender, and 
in close series, premaxillary teeth larger, and those of the dentary 
bone largest and stoutest, well-spaced; operculum about three- 
quarters as broad as deep. Hypocentra and pleurocentra large, 
well-ossified. Dorsal fin comprising 18 rays, arising in advance of 
the middle of the back, about as deep as long, and its maximum 
depth not much exceeding half that of the trunk at its origin; 
pectoral fins with loose fulcra ; pelvic fins arising opposite the front 
half of the dorsal; anal fin comprising only 9 or 10 rays, arising 
immediately behind termination of dorsal. Scales relatively large, 
some exhibiting a ver\ T feeble radiating crimping. 
