504 FISHES. 



backwaters on the shore, in which they rapidly grow to a 

 marketable size. Several species are more or less abundant 

 on the British coasts, as Mugil odo-radiatus (Fig. 105, p. 254), 

 3L capito, M. auratus (Fig. 106, p. 254), and il£ septcntrionalis 

 (Fig. 107, p. 254), which, with the aid of the accompanying 

 figures, and by counting the rays of the anal fin, may be 

 readily distinguished — M. odo-radiatus having eight, and M. 

 ccqyito and M. auratus nine soft rays. A species inhabiting 

 fresh waters of Central America {M. piTohoseidcus) has the snout 

 pointed and fleshy, thus approaching certain other fresh- 

 water and littoral Mullets, which, on account of a modifica- 

 tion of the structure of the mouth, have been formed into a 

 distinct genus, Agonostoma. Myxus comprises Mullets with 

 teeth more distinct than in the typical species. 



This genus existed in the tertiary epoch, remains of a 

 species having been found in the gypsum of Aix, in Provence. 



Twelfth Division — Acanthopterygii Gastrosteiformes. 



The spinous dorsal is composed of isolated sp)ines if present ; 

 the ventrals are either thoracic or have an ahdominal p)Osition 

 in consequence of the pirolongation of the pidjic hones which are 

 attached to the Ivumeral arch. Mouth smcdl, at the end of the 

 snout which is gcnercdly more or less 2>'i'odi(ced. 



First Family — G astro steidve. 



Body elongate, compressed. Cleft of the mouth oblique; 

 villiform teeth in the jaws. Opercular hones not armed ; in- 

 fraorhitals covering the check; j'fc^is of the skeleton formiyig 

 incomplete extcrned mciils. Scales no7ie, hit genercdly large 

 sctdes cdong the side. Isolated spines in front of the soft dorsal 

 fin. Ventral fins abdominal, joined to the ptibic bone, com- 

 posed of a spi7ic and a smcdl ray. Branchiostegals three. 



