174 
ACTINOPTERTan. 
Leptotrachelus armatus, W. von dor Marck. 
1863. Leptotrachelus armatus, W. von der Marck, Palmontogr. vol. *J. 
p. 59, pi. x. fig. 3. 
1885. Leptotrachelus armatus, W. von der Marck, ibid. vol. xxxi. 
p. 260. 
J ype. Imperfect fish ; Academy of Miinster, Westphalia. 
lhe type species, attaining a length of about 0‘5. Length of hca 
AV i th opercular apparatus contained about six times in the tota 
length to the base of the caudal fin. Anterior abdominal region 
excessively slender, a series of about 10 anterior vertebrae equalling 
the length of the head. Pelvic fins much larger than the pectorals, 
arising at about the middle point, of the trunk. Dermal scutes 
of abdominal region excessively attenuated, those of the caU a 
region robust. 
Form. <f* Loc. Upper Cretaceous : Westphalia. 
P. 2109. Imperfect head and abdominal region, with remains of th® 
fins ; Sendenhorst. Eyerton Co 
Leptotrachelus triqueter, Pictet. 
1850. Dercetis triqueter, F. J. Pictet, Poiss. Foss. Mont Liban, p- ' 
pi. ix. figs. 5, 6. g 
1850. Dercetis linguifer, F. J. Pictet, ibid. p. 47, pi. ix. ho 8, ’ 
[Fragment of abdominal region ; Geneva Museum.] . 
1866. Leptotrachelus triqueter, Pictet & Humbert, Nouv. Rech. P° 19 
Foss. Mont Liban, p. 95, pi. xiv. figs. 1,2. . q 
1887. Leptotrachelus triqueter, J. W Davis, Trans. Roy. Dublin 0 
[2] vol. iii. p. 620, pi. xxxviii. fig. 1. 
Type. Fragment of abdominal region ; Geneva Museum. 
A species attaining a length of about 0'3. Head with opercu 
apparatus occupying about one fifth of the total length of the fi» 
the base of the caudal fin. Anterior abdominal region not exe 
sivcly elongated, its vertebral centra, about twice as long as eeP’ 
and a series of 16 or 17 equalling the length of the head ; the o 
vertebra nearly similar in proportions. Pectoral fins each xvi 
about 11 rays, the length of the longest equalling one third tba ^ 
the head with opercular apparatus ; pelvic fins slightly larger * 1 
the pectorals, arising just behind the anterior third of the * ru ^ 
each with not less than 7 or 8 rays ; dorsal fin occupying 
middle third of the trunk, with about 35 ravs, the hinderm 
comparatively small and slender; anal fin with about 8 rays, tw 1 
as distant from the pelvic pair as from the caudal. Dermal 8C “ ' 
o moderate size and narrow, those on the dorsal and vlU 
or ers of the caudal region bearing a backwardly-directed smoo 
