PACHYCORMIDJE. 
377 
and contained seven times in the total length. Pelvic fins arising a 
little in advance of the middle point between the pectoral and anal 
fins; dorsal and anal fins directly opposed, each with about 18rays, 
arising somewhat behind the middle point of the trunk. Scales 
smooth. 
Form. <$f Log. Upper Lias: Yassy, Yonne, Prance. 
Not represented in the Collection. 
Genus EUTHYNOTUS, Wagner. 
[Gelehrte Anzeig. k. hay. Akad. Wiss. vol. 1. 1860, p. 214.] 
Svn. Cyclospondylus , F. A. Quenstedt, ILandb. Petrefakt. ed. 2, 1867, 
p. 260. 
Heterothrissops , H. E. Sauvage, Bibl. Ecole Hautes Etudes, 
vol. xiii. no. 5, 1875, p. 46. 
Pseudothrissops, IL E. Sauvage, ibid. p. 46. 
Parcithrissops, H. E. Sauvage, Bull. Soc. Sci. Yvonne, vol. xlv. 
pt. ii. 1891, p. 37. 
A genus differing only from Sauropsis in the presence of well- 
developed hypocentra and pleurocentra surrounding the notochord, 
and in exhibiting minute fulcra on the median fins. 
Buthynotus incognitas (Blainville). 
1818. Esox incognitus, H. D. de Blainville, Nouv. Diet. d’Hist. Nat. 
vol. xxvii. p. 325. 
1833-44. Thrissops micropodius , L. Agassiz, Poiss. Eoss. vol. ii. pt. i. 
p. 12; pt. ii. p. 126, pi. lxv. 
1848. Sauropsis micropodius , C. G. Giebel, Fauna der Vorwelt, Fische, 
p. 200. 
1852. Thrissops micropodius , F. A. Quenstedt, Handb. Petrefakt. p. 218, 
pi. xvii. fig. 18. 
1858. Thrissops micropodius , F. A. Quenstedt, Der Jura, p. 237, 
pi. xxxiii. figs. 3-7. 
1860. Euthynotus micropodius, A. Warner, Gelehrte Anzeig. k. bav. 
Akad. Wiss. vol. 1. p. 218. 
1867. Cyclospondylus , F. A. Quenstedt, Handb. Petrefakt. ed. 2, p. 260. 
1875. Pseudothrissops micropodius (errore micropterus ), H. E. Sauvage, 
Bibl. Ecole Hautes Etudes, vol. xiii. no. 5, p. 46. 
1887. Euthynotus micropodius , K. A. von Zittel, Handb. Pakeont. 
vol. iii. p. 225, woodc. fig. 238. 
Type. Nearly complete fish; Paris Museum of Natural History. 
The type species, attaining a length of about 0*35. Length of 
head with opercular apparatus equalling somewhat more than one- 
fifth of the total length to the base of the caudal fin, and exceeding 
