39 



II. Caudal fin none, tail in most cases prehensile. 



1. Body depressed or subcylindrical. 



a. Snout very slender, twice as long as remaining part 

 of head. Praenuchal and two nuchal shields present. 



Tail filiform but not prehensile Stigmatophora p. 97. 



b. Snout rather stout, nearly twice the length of post- 

 orbital part of head. No praenuchal shield. Tail 



prehensile _ Syngnathoides p. 39. 



2. Body compressed, not or scarcely dilated. Tail pre- 

 hensile. 



a. Base of dorsal not elevated ; dorsal situated on tail 



only. No cutaneous appendages. Operculum without 



keel, but with smooth or serrated radial ridges. . Solegnathus p. 65. 

 I. Base of dorsal elevated; dorsal situated on trunk 



and tail. Operculum with convex keel bent upwards 



to branchial opening. 



1. Longitudinal axis of head and trunk nearly in 

 the same plane. Praenuchal shield without a co- 

 ronet; numerous long cutaneous appendages . . Hallichthys p. 105. 



2. Longitudinal axis of head forming a right angle 

 with axis of trunk. Praenuchal shield surmounted 

 by a coronet; cutaneous appendages generally 



absent Hippocampus p. 106. 



i. Syngnathoides Bleeker ! ). 



(BLEKKEK, Nat. Tijdschr. Ned. Indie II. 1851, p. 231 and 259. Verh. Batav. 



Genootsch. XXV. 1853, Bijdr. Kennis Troskieuwige visschen, p. 5, 9 and 12). 



Gastrotokeus Kaup, Arch. f. Naturgesch. XIX. j, 1853, p. 230 and Cat. 



Lophobranchiate Fish, London 1856, p. 18. 



Body elongate, depressed, tetragonal; with narrow dorsal 

 surface. The ventral surface much broadened, limited by the 

 median lateral cristae (lateral lines) and in the male covered 

 by soft skin in which the eggs are embedded, uncovered by 

 cutaneous folds, or scutal plates. Tail shorter than head and 

 body, hexagonal in its subdorsal part, furtheron quadrangular, 

 rapidly tapering, without caudal arid prehensile. Superior 

 cristae of trunk and tail as also the inferior cristae continuous, 

 which are not conspicuous on the trunk. Posterior end of 

 median cristae (lateral lines) bent upwards and reaching the 

 superior cristae behind dorsal or nearly so (Fig. 17, 4). No 



i) We have shown (Zoolog. Mededeel. Museum Leiden. VI. i. 1921, p. 67), 

 that Syngnathoides Bleeker 1851 has precedence before Gasterotokeus Kaup 1853. 



