194 Dr. A. Smith Woodward—Fish-remains, Brazil. 
trunk there are traces of the expanded bases of the neural and heemal 
arches, which must have nearly encircled the persistent notochord ; 
and just above these expansions in the neural arches of the abdominal 
region the interdigitating plates, which form a rigid connection 
between the bases of the neural spines, are conspicuous. The ribs 
are winged as described by Cope, but the appearance of a “‘ continuous 
wall”’ noted by him is partly due to an inner view of the underlying 
scales of the left side of the fish. Impressions show that the hemal 
spines within the caudal fin are fan-shaped. The slender left clavicle 
still retains traces of its inferior expansion (el.), which is mistaken by 
Cope for a coracoid bone; while the series of basal bones of the 
_ pectoral fin is obviously incomplete, and so does not place the 
. Pyenodontidee in the Isospondyl, as supposed by Cope. All the fins 
are very imperfect, and it is impossible to determine how many rays 
were originally present in the dorsal and anal fins, which are 
incomplete in front. There is thus no reason for Cope’s conclusion 
that the anal fin is unusually short. ‘The caudal fin, which is shown 
chiefly as an impression, displays the peculiar shape characteristic of 
Paleobalistum. Remains of the squamation occur over the whole of 
the abdominal region and, though more delicate, over the middle part 
of the flank of the caudal region; but the scales are represented 
chiefly by their thickened ribs (‘rhabdopleurs’ of Cope), by which the 
transverse rows are clearly spliced together in the usual manner. 
Cope did not observe this splicing, but described the ‘rhabdopleurs’ as 
“‘not segmented.” As noted by him, the number of transverse rows 
of scales is equal to that of the vertebral segments. No traces of 
scale-ornament are observable. 
The condition of the vertebral column and phe shape of the caudal 
pedicle and caudal fin prove that the Pyecnodont now described belongs 
to the genus Palgobalistum, which occurs both in the Upper Cretaceous 
and in the Eocene of the Old World. It differs from P. Ponsorti 
(Upper Cretaceous, Marne, France), in having the scales continued 
over the middle of the flank of the caudal region; but agrees mm the 
latter respect both with the type-species, P. orbiculatum’. (Upper 
Kocene, Monte Boleca), and with P. Goedeli (Cretaceous, Hakel, 
Mount Lebanon). In the strength of this caudal squamation the 
Brazilian fish is intermediate between the two last-mentioned species, 
but in the shape of its caudal fin resembles most closely P. Goedel. 
Palaobalistum flabellatum was discovered in ‘ the southern centre of 
the Province of Sergipe del Rey.” 
Apocopopon sEricEus, Cope. (Pl. VII, Figs. 4, 4a, 46, 5, 5a.) 
1886. -Apocopodon sericeus, EK. D. Cope: Proc. Amer. Phil. Soc., vol. xxiii, p. 2. 
I have already remarked® that the dentition haan Apocopodon 1s 
intermediate between that of the typical Myliobatide and that of the 
1 Tn the British Museum Catalogue of Fossil Fishes, pt. iii (1895), scales are said 
to be confined to the anterior half of the trunk in P. orbzeulatiwm; but an example of 
this species acquired by the British Museum since 1895 shows numerous very delicate 
ribs of scales in the caudal region. (B.M. No. P. 9830, described and figured by 
Heckel: Denkschr. k. Akad. Wiss. Wien, math.-naturw. Cl., vol. x, p. 229, pl. x.) 
2 Proc. Geol. Assoc., vol. x (1888), p. 297. 
