Fishes of the IVestern North Atlantic 



63 



developmental stages (Collinge, 75: 265, pi. 4, fig- 2 ; j^: 511, 512; Landacre and 

 Conger, 42: 593, 594; Hammarberg, 2g\ 309, figs. 39-43). A small sliver-shaped 

 bone is present, at least in the young, at the angle of the mouth; this bone is continuous 

 with the preorbitals in its dentition but is not traversed by the infraorbital canal; thus 

 it is considered to represent the maxillary. The vomer is paired. There is no opisthotic 



Figure ii. Lefisosteus spatula. Caudal fin skeleton; original drawing (natural size) of a specimen from Lake 

 Pontchartrain, Louisiana. 



(Mayhew, ^7: 327), supraoccipital, gular plate, or myodone in the Garfishes. The lower 

 jaw, a complex of six dermal bones — dentary, articular, angular, preangular, prearticu- 

 lar, and coronoid (Arambourg and Bertin, 2^: 2185, fig. 1546) — articulates in front 

 of the eye. The sacculus and lagena form a common sac, the largest otolith being in 

 the former. Three pairs of branchiostegals support the gill membrane. The opercular 

 gills are especially well developed in the Garfishes, an upper horizontal "arm" and a 

 bisegmented lower one being noticeable (Wright, y6\ 483). 



The dorsal fin is situated posteriorly, above the anal fin. The fins are without 

 spines, and the rays of the dorsal and anal fins are equal in number to the supporting 

 radialia. There is no adipose fin. 



The body of the adult is completely encased in an armor of rhombic ganoid scales, 

 which may be denticulated and sculptured on the exposed surface.'- Most of the scales 



2. The degree of sculpturing is of some taxonomic value when specimens of comparable size are used. 



