CLUPEID^. 
131 
Genus HISTIOTHRISSA, novum. 
H ead and trunk laterall}^ compressed. Cleft of mouth extending to 
the hinder border of the orbit; maxilla robust and arched, with two 
large supramaxillary bones ; margin of jaws with regular series of 
very small pointed teeth, Branchiostegal rays about 12 in number. 
Gill-rakers very large. Vertebrae between 40 and 50 in number, 
about 20 being caudal ; the centra about as long as deep, all con¬ 
stricted and marked with small longitudinal ridges. Fins relatively 
large, but no rays excessively elongated; postclavicular plates 
slightly dilated and smooth ; foremost ray of paired fins articulated, 
but not divided, and length of pectoral fin at least equal to the 
space between the origin of the pectoral and pelvic fins ; dorsal fin 
deeper than long ; anal fin longer than deep, and less elevated than 
the dorsal fin; caudal fin forked. Scales of moderate size, very 
deeply overlapping, none pectinated; no enlarged or thickened 
ridge-scales ; lateral line inconspicuous. 
Histiothrissa macrodactyla (W. von der Marck). 
1858. Sardimns macrodacf^lus, W. von der Marck, Zeitschr. deutsch. 
geol. Ges. vol, x. p. 245. 
1863. Sardinius macrodactylus, W. von der Marck, Palaeontogr. vol. xi. 
p. 44, pi. vi. fig. 1. 
Type. Nearly complete fish ; Academy of Munster. 
The type species, attaining a length of about 0*25. Length of 
head with opercular apparatus considerably exceeding the maximum 
depth of the trunk and contained twice in the length from the 
pectoral arch to the base of the caudal fin. Pectoral fins with 
17 rays, the length of the foremost very slightly exceeding the 
'maximum depth of the trunk; pelvic fins with 10 rays, two thirds 
as large as the pectorals, and opposed to the middle of the dorsal; 
.dorsal fin with about 17 rays, the foremost two short and spinous, 
the next ray longest and articulated though not divided distall}', 
arising about twice as far from the caudal fin as from the occiput; 
anal fin with 18 rays, the foremost three as in the dorsal, arising 
midway between the pelvic pair and the caudal. 
The so-called Sardinius rohustus (W. von der Marck, Palaeontogr. 
vol. XV. 1868, p. 284, pi. xlii. fig. 2, and vol. xxxi. 1885, p. 254, 
pi. xxiii. fig. 1) is scarcely distinguishable from this species. 
Form. Log. Upper Cretaceous : Westphalia. 
P. 2104. Finely preserved specimen about 0-23 in length ; Senden- 
horst. The mouth is opened by crushing, and there are 
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