162 
ACTINOPTERTGII. 
holm, Forhandl. vol. xv. (1893), p. 574.—Pleistocene; 
Skattmanso, Upland, Sweden. 
^ Osmerus albyi^ H. E. Sauvage, Ann. Sci. Geol. vol. iv. (1873), 
art. no. 1, p. 215, fig. 53.—Upper Miocene; Licata, 
Sicily. [Imperfect fish.] 
Osmerus cVacJiiardi, de Bosniaski, Atti Soc. Tosc.—Proc. Yerb. 
vol. i. (1878), p. xix (name only).—Upper Miocene; 
Gabbro, Tuscany. 
Osmerus larteti, H. E. Sauvage, loc. dt, 1873, p. 213, fig. 41, and 
loc. cit. vol. xi. (1880), art. no. 3, p. 40, fig. 11.—Ibid. 
[Ditto.] 
^ Osmerus 'propterygius^ H. E. Sauvage, ibid. p. 216, figs. 54,62.—- 
Ibid. [Ditto.] 
A Osmerus scarabellii^ I. Bonomi, Eivista Ital. Paleont. vol. ii. (1896), 
p. 218, pi. V. fig. 6.—Upper Miocene; Mondaino, Prov. 
Forli, Italy. [Ditto.] 
^ Osmerus (?) stilpiios, H. E. Sauvage, loc. cit. 1873, p. 218, figs. 55, 
63.—Ibid. [Ditto.] 
The generic determination of these supposed species of Osmerus 
is very doubtful. 
Family HALOSAURID^E. 
Trunk much elongated, the caudal region relatively large and 
tapering. Parietal bones in contact, excluding the supraoccipital 
from the cranial roof; squamosals suturally united with parietals 
and completely covering the otic region ; snout a little produced; a 
suborbital series of enlarged cheek-plates bearing the well-developed 
slime-canal. Mandibular suspensorium inclined forwards, and 
g-ape of mouth small; premaxilla chiefly forming the upper border 
of the mouth, but maxilla also entering it; teeth minute or rudi¬ 
mentary. Oj)ereular apparatus incomplete, with numerous well¬ 
spaced slender branchiostegal rays, but no gular plate. Vertebral 
centra in the form of thin cylinders jnerced by the notochord; ribs 
very short. Intermuscular bones present. Fin-fulcra absent; fin- 
rays bifurcated slightly and articulated at wide intervals in the 
distal half; pectoral fins placed well upon the flank,, and pelvic fins 
well-developed, abdominal; a single dorsal fin about the middle of 
the back; anal fin much extended, sometimes confluent with the 
caudal. Scales thin and cycloid ; lateral line conspicuous along the 
ventral portion of the flank. 
This family survives only in the deep sea, where it is represented 
by Halosaurus and one or two other closely related genera. An 
