COLLETTE ET AL.: BELONIFORMES 



339 



Fig. 172. Adrianichthyidae egg. Horaichthys selnai. (From: Kul- 

 kami, 1940.) 



filaments of what they called Hemiramphus marginatus (Fig. 

 175C) and Hyporhamphus qitoyi, respectively, to be grouped in 

 tufts. The filaments in a tuft may be of different lengths (e.g.. 

 He. marginatus). 



Most exocoetids have eggs that are attached with thin thread- 

 like filaments to objects floating in the water column or to sea- 

 weed growing near shore. The size and structure of the eggs and 

 the size, nature, and location of the filaments vary among species. 

 The eggs of Fodiator and Prognichthys have uniformly-spaced 

 filaments (Fig. 176B). Filaments on Hirundichthys eggs have a 

 bipolar arrangement. One species, H. coromandelensis, has three 

 types of filaments (Vijayaraghavan, 1973), but they are grouped 

 in a bipolar distribution. This type of egg has a single long (103 

 mm), stout filament arising from the basal pole, which is sur- 

 rounded by 3-5 medium length (.v = 4.6 mm) filaments. Five 

 to 1 2 short (.V =1.1 mm) filaments are located at the distal pole 

 (Fig. 1 76C). Chorionic filaments in Parexocoetus. Cheilopogon 

 and Cypselurus vary. Some species have uniformly-spaced fil- 

 aments, whereas others have a bipolar arrangement with the 

 filaments usually longer at one pole than at the other. Unlike 

 all other flying fishes, species of Exocoetus have eggs with a 

 smooth membrane, devoid of filaments (Fig. 176A). 



Larvae 



A relatively long incubation period is typical of the Beloni- 

 formes (Kovalevskaya, 1982). The eggs develop for one to two 

 weeks, and the larvae are well formed and capable of actively 

 capturing food at hatching. Time of development is comparable 

 in pelagic and attaching eggs. Following a pattern similar to that 



Fig. 173. Scomberesocidae eggs. (A) Scomberesox saurns. SWFC 

 Cr. Est 1-4 Sta. Surf. I; (B) Cololabis saira. SWFC CalCOH. (Original.) 



reported for egg size, belonids hatch at the largest sizes (6.8- 

 14.4 mm) followed by hemiramphids (4.8-11 mm), scomber- 

 esocids (at least as small as 6.0-8.5 mm), exocoetids (3.5-6.1 

 mm), and adrianichthyids (3.5-4.5 mm). 



Gut length differs between the two suborders. Adrianichthy- 

 oid larvae have a short gut, as in Atheriniformes and Cyprin- 

 odontiformes, 40-50% of standard length (Fig. 177A). Exocoe- 

 toid larvae are generally elongate and have a straight gut extending 

 approximately two-thirds the standard length (Fig. I77B-E, G, 

 and H). 



Presence of a preanal finfold appears to be plesiomorphic. 

 Job's (1940) illustration of a yolk-sac adrianichthyoid, Oryzias 

 melastigma. shows a preanal finfold (Fig. 1 77A), but Kulkami's 

 ( 1 940) illustration of a yolk-sac Horaichthys setnai does not. A 

 preanal finfold is present until after formation of all fins in the 

 belonids, hemiramphids and scomberesocids (Fig. I77B-E). The 

 situation in the Exocoetidae is not clear. Most published illus- 

 trations of exocoetids do not show a preanal finfold. Ones that 



