MACR0SEMIID2E . 
177 
of the middle of the flank relatively large, becoming smaller both 
dorsally and ventrally, in the former case by dichotomy of the 
vertical series; about four very large ridged-scales on the ventral 
border between the anal and caudal fins. 
Macrosemius rostratus, Agassiz. 
[Plate III. fig. 4.] 
1834. Macrosemius rostratus , L. Agassiz, Neues Jahrb. p. 388 (name 
only). 
1844. Macrosemius rostratus, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 
p. 150, pi. xlvii. a. fig. 1. 
1851. Macrosemius rostratus, A. Wagner, Abb. k. bay. Akad. Wiss., 
math.-phys. Cl. vol. vi. p. 73. 
1863. Macrosemius rostratus, A. Wagner, ibid. vol. ix. p. 647. 
1863. Macrosemius insignis, A. Wagner, ibid. vol. ix. p. 648, pi. ii. 
[Fish, wanting tail; Palaeontological Museum, Munich.] 
Type. Nearly complete fish; Royal Bohemian Museum, Prague. 
The type species, attaining a length of about 0*3. Head with 
opercular apparatus somewhat longer than its maximum depth and 
occupying about one-quarter of the total length of the fish; the 
maximum depth of the trunk exceeding twice the width of the 
caudal pedicle. Bays of dorsal fin very long and comparatively 
slender, without denticles, and about 38-40 in number; the length 
of those of the hinder portion of the caudal region greater than the 
depth of that part of the trunk. Pelvic fins arising well in advance 
of the middle point between the pectoral and caudal fins, and the 
anal arising shortly behind. Scales conspicuously pectinated. 
Closely related to this fish, if not specifically identical, is a trunk 
from the Lithographic Stone of Kelheim, said to be slightly deeper 
in proportion to its length but not otherwise distinguished from 
the typical M. rostratus. It is described as the type of M. latiusculus 
by A. Wagner, Abh. k. bay. Akad. Wiss., math.-phys. Cl. vol. vi. 
(1851), p. 74; and a head is figured under the same name by 
K. A. von Zittel, Handb. Palaeont. vol. iii. (1887), p. 218, fig. 232 
(copied above, fig. 29, p. 163). The original specimens are pre¬ 
served in the Palaeontological Museum, Munich. 
Form. &f Loc. Lower Kimmeridgian (Lithographic Stone): Bavaria. 
37051. Fine specimen 0-275 in length, in counterpart, displaying 
some of the teeth, a few ribs, the dorsal and caudal fins, 
and the greater part of the squamation ; Solenhofen. 
Hdherlein Coll. 
x 
PART III. 
