STIfGXATHID^. 
381 
pectoral, anal, and caudal fins variable. Trunk more or less 
encased in rings of bony plates ; no scales. 
Small coast fishes living among seaweeds in temperate and 
tropical regions, swimming chiefiy by peculiar motion of dorsal fin. 
Synopsis of Genera ivith Extinct Representatives. 
All with axis of head in continuation of that of trunk ; with caudal fin 
and non-prehensile tail. 
Trunk much elongated; dermal armour incom¬ 
plete, probably absent on caudal region .... Pseudosyngnatlms 
Trunk much elongated; dermal armour complete ; [(p. 381). 
clavicular arch not rigid at lower end; anal 
fin minute .... Eiplxonostoina 
As Siphonostoma, but clavicular arch rigid at [(p. 382). 
lower end. Syngnatlius (p. 382). 
Trunk only moderately elongated ; dermal armour 
complete ; all median tins well developed .. Calamostoma 
[(p. 383). 
Genus PSEUD OS YNGNATHUS, Kner & Steindacbner. 
[Denkschr. k. Akad. Wiss., math.-naturw. Cl. vol. xxi. 1863, p. 28.] 
Trunk much elongated, not dilated. Pectoral fins present; 
dorsal fin small and very remote; caudal fin small, truncated 
behind. Dermal armour apparently incomplete, perhaps wanting 
on the caudal region. 
According to Kner and Steindachner, the form and disposition of 
the supports of the dorsal fin suggest that its rays had not the 
peculiar power of motion observed among existing Syngnathidoe. 
Pseudosyngnathus opisthopterns (Agassiz). 
1796. Syngnatlius typlile, G. S. Volta, Ittiolit. Veronese, p. ccxxxix. 
pi. Iviii. fig. 1 {errore). 
1818. Syngnatlius tyyhle, II. D. de Blainville, Nouv. Diet, d’llist. Nat. 
vol. xxvii. p. 339 (errore), 
1833-44. Syngnatlius opistliopterus, L. Agassiz, Poiss. Foss. vol. ii. pt. i. 
p. 18, pt. ii. p. 276. 
1863. Pseudosyngnathus opistliopterus.^ Kner & Steindachner, Denkschr. 
k. Akad. Wiss/, math.-naturw. Cl. vol. xxi. p. 29, pi. vi. fig. 1. 
, 
Type. Imperfect fish; Museum of Natural History, Pans. 
The tjme species, attaining a length of about 0*35. Vertebrae 
apparently between 55 and 60 in number. Dorsal fin just within 
hinder quarter of back, with 8 or 9 rays; caudal fin with 13 or 
