350 
ACTINOri'ERYGII. 
the total length to the base of the caudal fin. Pectoral fins l° n ° 
and narrow ; pelvic fins approximately midway between the pectora 
and caudal fins; space between occiput and origin of dorsal u 
about equal to length of cranium ; anal fin probably with about 
rays. 
Form. Sf Loc. Neocomian : Voirons, Switzerland ; Hanover. 
1897. 
P. 8639. Imperfect fish, 0-21 in length, exhibiting general P r ° ; 
portions and most of its ossential characters; “Hilsthoni 
Hildesheim, Hanover. The mouth is shown, an 
great extent of tho dorsal fin is indicated by fragmen^ 
The courso of the simplo lateral line is traceable low 
the flank of tho anterior abdominal region. 
Presented by Prof. A. von Koenen, 
P ■ 7184 a. Somewhat larger head and abdominal region; “Hilatho^ 
Hildesheim. Tho contours of tho displaced premaxi^ 
and mandible are distinct. The preoperculum is ® ^ 
siderably expanded at the angle and is shown to ^ 
been marked with delicate radiating grooves. The °_ n ^ g 
of the dorsal fin is indicated by remains of a few •’P 1 ® ^ 
rays. The course of the lateral line, low on the 
and gradually rising behind, is conspicuous. . 
Purchased, 
P. 8640-43. Three small imperfect specimens, of which tw o ar ^ 
counterpart, also a detached tail as large as that o ^ 
type specimen ; “ Hilsthon,” Hildesheim. No. • 
shows tho extent of the dorsal and anal fins, but o ^ . Q 
too imperfect for precise description. The ana 
great part opposed to the hinder portion of the 016 _ 
Presented by Prof. A. von Koenen, 
P. 7184-85. Two small imperfect specimens, tho first sbowin,,^^ 
small, slender, mandibular teeth, and also an linpr 
of the characteristic, expanded preoperculum up 
above the head ; “ Hilsthon,” Hildesheim. col 
Purchased, 
Genus SYLL^IMUS, Cope. 
[Vert. Cret. Form. West (ltep. U.S. Geol. Surv. Territ. vol. »• 
1875), p. 180.] _ ffl0re 
Apparently differing from Crossognathus only in the ■- g n _ 
remote position of the pelvic fins and the absence of an 
