(JLUl'EIMi. 
131 
Genus HISTIOTHRISSA, novum. 
Head and trunk laterally 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 1*2 in number. 
Gill-rakers very large. Vertebra) between 40 and 50 in number, 
about 20 being caudal ; the contra 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 tins articulated, 
but not divided, and length of pectoral tin 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 ; latoral line inconspicuous. 
Histiothrissa macrodactyla (\Y. von dcr Marck). 
1858. Sardimvs macrodacti/lux, W. von del - Marck, Zeitsclir. deutsch. 
geol. Ges. vol. x. p. 245. 
1863. Sardinius macrodaetylus, W. von der Marck, Pakeontogr. 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 distally, 
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 robuslus (W. von der Marck, Paltoontogr. 
vol. xv. 1868, p. 284, pi. xlii. fig. 2, and vol. xxxi. 1885, p. 254, 
pl. xxiii. fig. 1) is scarcely distinguishable from this species. 
Form. <$- Lor. Upper Cretaceous : Westphalia. 
!*• 2104. Finely preserved specimen about 023 in length ; Senden- 
horst. Tho mouth is opened by crushing, and there are 
k 2 
