PACHYCORMIDJE. 
383 
while the form and proportions of the head and operculnm are 
regarded as the most important specific characters. 
Pachycormus macropterus (Blainville). 
1755. Figure by A. J. Dezallier d’Argenville, Oryctologie, pi. xviii. 
fig. 1. 
1805. Figure by B. Faujas St. Fond, Essai de Geologie, vol. i. p. 122, 
pi. viii. 
1818. Flops macropterus, H. I), de Blainville, Nouv. Diet, d’llist. Nat. 
vol. xxvii. p. 324. 
1833-44. Pachycormus macropterus , L. Agassiz, Poiss. Foss. vol. ii. 
pt. i. p. 12; pt. ii. p. Ill, pi. lix. a. 
1848. Pachycormus macropterus , C.G. Giebel, Fauna d. Vorw., Fische, 
p. 197. 
1858. Pachycormus macropterus , F. A. Quenstedt, Der Jura, p. 236, 
pi. xxxii. fig. 5. 
1860. Pachycormus macropterus , A. Wagner, Gelehrte Anzeig. k. bay. 
Akad. Wiss. vol. 1. p. 221 (in part). 
1883. Pachycormus macropterus, H. E. Sauvage, Bull. Soc. Linn. 
Normandie, [3] vol. vii. p. 144, pi. iv. 
(P) 1887. Pachycormus macropterus, K. A. vonZittel, Handb. Palaeont. 
vol. iii. p. 224, fig. 237. 
Type. Nearly complete fish ; Paris Museum of Natural History. 
The type species, attaining a length of about 1-0. Head with 
opercular apparatus occupying somewhat more than one-quarter of 
the total length of the fish; head much elongated and snout obtuse, 
the ratio between the length of the head from the median elevation 
to the end of the snout and the width of the head near the occiput 
being 9:7; operculum triangular, almost or quite as broad as deep, 
and branchiostegal rays about 50 in number. Dorsal fin with about 
30-35 rays, arising at the middle point of the back and well in 
advance of the anal fin, which is equally extended. Scales of mode¬ 
rate size, mostly smooth but in part faintly rugose. 
Form. Sf Log. Upper Lias : N. and E. France ; AViirtemberg ; 
Somersetshire & Yorkshire. 
20657. Specimen 0‘96 in length, with imperfect head ; Boll, Wiir- 
temberg. The anal fin is shown well behind the dorsal, 
and about 28 rays can be counted in each. 
Purchased , 1846. 
P. 7569. Imperfect fish about 0"7 in length; Ohmden, Wiirtemberg. 
Some of the dorsal scales are ornamented with a faint 
rugosity. Purchased. 
