414 
ACTINOPTERYGII. 
originally regarded by Cope (toe. cit. 1875, p. 244 a) as representing 
a previously unknown order of Actinopterygian fishes, named Acti- 
nochiri. The American specimens are described as exhibiting “ six 
single and one paired basilar bones supporting the pectoral fin, and 
all articulating with the scapula.” The following forms, not repre¬ 
sented in the Collection, are distinguished :— 
Pelecopterus chirurgus, E. D. Cope, Vert. Cret. Form. West (Rep. 
U.S. Geol. Surv. Territ. vol. ii. 1875), p. 244 b, woodc. 
fig. 10, pi. xlviii. fig- 1, pi. liv. fig. 9.—Upper Cretaceous 
(Niobrara Group); Kansas. 
Pelecopterus gladius , E. D. Cope, loc. cit. (1875), p. 244 e, pi. lii. 
fig. 3, pi. xliv. fig. 12 : Portheus gladius , E. D. Cope, 
Proc. Acad. Nat. Sci. Philad. 1873, p. 338, and Bull. U.S. 
Geol. Surv. Territ. vol. i. no. 2 (1874), p. 40.—Ibid. /\P!.\/.H. 
Pelecopterus perniciosus , E. D. Cope, loc. cit. (1875), p. 244 d, 
pi. xlviii. fig. 2, pi. lii. fig. 2, pi. xliv. fig. 13 : Ichtliyo- 
dectes perniciosus , E. D. Cope, Bull. U.S. Geol. Surv. Territ. 
^ Tf.//,/ vol. i. no. 2 (1874), p. 41.—Ibid./ [The type species of 
Pelecopterus , referred to Protospliyrcena nitida by A. R. 
Crook, Palaeontogr. vol. xxxix. (1892), p. 110.] 
To the Pachycormidae may also perhaps be referred the large 
problematical fish from the Oxford Clay of Peterborough named 
Leedmi problematical (A. S. Woodward, Geol. Mag. [3] vol. vi. 1889, 
p. 451 \Leedsichthys problematicus\ and ibid. vol. vii. 1890, p. 292, 
pi. x. figs. 9, 10). The type specimens from the Leeds Collection 
are now preserved in the Museum, but the determination of all the 
bones except the gill-rakers (? or gill-supports) is still so uncertain, 
that it seems advisable to postpone the description of them until the 
final Supplement, when more satisfactory evidence of their true 
nature may perhaps be forthcoming. The massive bones, which 
have been compared with branchiostegal rays, will most likely prove 
to be vertebral arches. The genus also occurs in the Oxford Clay 
of Yaches Noires, Normandy, and in the Kimmeridge Clay of 
Dorsetshire. 
