AMIIDUi. 
301 
L. Schmidt, “ Untersuchungen zur Kenntniss des Wirbelbaues 
von Amia calvci ” (Zeitschr. f'. wiss. Zool. vol. liv. 1892, 
pp. 748-764, pi. xxxiv.). 
Synopsis of Genera. 
I. Vertebral elements rudimentary- or absent; 
dorsal fin short-based. 
Trunk elongate, scarcely tapering; fulcra 
wanting; caudal fin rounded or only 
slightly forked. 
II. V ertebral elements forming complete discs; 
dorsal fin more or less extended. 
Dorsal fin not occupying more than the middle 
third of the back. 
Dorsal fin occupying more than half the 
length of the back. 
Liudesmus (p. 361). 
Megalurus (p. 363). 
Amia (p. 367). 
Genus LIODESMUS, W agner. 
[Abh. k. bay. Akad. Wiss., math.-phys. Cl. vol. ix. 1863, p. 709.] 
Syn. Lophiurus, B. Vetter, Mittheil. k. mineral.-geol. Mus. Dresden, 
pt. iv. 1881, p. 116. 
Trunk elongate, scarcely tapering to the caudal pedicle. Head 
relatively large, with obtuse snout; marginal teeth all large and 
well-spaced. Notochord persistent, without ossifications in the 
sheath. Fin-fulcra wanting. Dorsal fin short-based, opposed to 
the pelvic pair ; caudal fin fan-shaped or slightly bifurcated. Scales 
very small. 
Liodesmus gracilis (Agassiz). 
1838- 44. Pholidophorus gracilis, L. Agassiz (ex Munster, MS.), Poiss. 
Foss. vol. ii. pt. i. p. 285, pi. xlii. fig. 2. 
1839- 44. Meg alurus parvus, L. Agassiz (ex Munster, MS.), ibid. vol. ii. 
pt. ii. p. 149, pi. Ii. fig. 4. [Nearly complete fish ; Palaeontological 
Museum, Munich.] 
1851. Meg alurus parvus, A Wagner, Abh. k. bay. Akad. Wiss., math.- 
phys. Cl. vol. vi. p. 70. 
1851. Megalums intermedius, A. Wagner (ex Munster, MS.), ibid. 
p. 71. [Nearly complete fish; Palaeontological Museum, Mu¬ 
nich.] 
1863. Liodesmus gracilis, A. Wagner, ibid. vol. ix. p. 711. 
Type. Vertically crushed fish ; Palaeontological Museum, Munich. 
The type species, attaining a length of about 0*06. Head with 
opercular apparatus occupying somewhat less than one-quarter of 
