no. 3617 PERCIFORM FISHES — GOSLINE 33 



1967). In the caudal skeleton of Scomber (fig. be), the upper and the 

 lower hypural plates remain separate with a notch between them, 

 and the preurostylar vertebra has no attached neural arch; by con- 

 trast, in such an advanced scombrid as Thunnus (fig. bf), the upper 

 and lower hypurals have fused into a single plate without a median 

 notch and the preurostylar vertebra seems to have a well developed 

 neural arch (fig. 5/: NA), though this may represent a fusion between 

 the anterior epural of Scomber (fig. be) and the preurostylar centrum 

 (cf. Gregory and Conrad, 1943, fig. 5d). 



Among the trichiuroid fishes, increasing degrees of morphological 

 specialization are shown by the series Scombrolabracidae-Gempylidae- 

 Trichiuridae. Since no account of the osteology of the basal member 

 of the series, namely Scombrolabrax (fig. 6), has ever been given, one 

 is presented below. 



The Osteology of Scombrolabrax 



Figures bd, 6 



Teeth. — The jaw teeth are all well separated from one another, 

 and all point more or less backward. They are in single rows except 

 for one to three inner teeth near the midline of each jaw; these inner 

 teeth of the upper jaw are needle-like fangs and are by far the largest 

 in the mouth, but the inner teeth of the lower jaw are small. The outer 

 row in each jaw is made up of well separated, sharp, distally-proximally 

 flattened teeth; those along the sides of the lower jaw are much the 

 larger. There is a single row of small teeth on each palatine and a 

 V-shaped row on the vomer. Mesopterygoid toothless. 



There are three patches of needle-like teeth on the upper pharyngeals 

 of each side; the separate lower pharyngeals have similar teeth. 



On the first arch are five lathlike gill rakers that, however, have 

 spines projecting from their posterior border. The other gill rakers are 

 in the form of low, spinulose platelets. On the rear face of the anterior 

 arch and on succeeding arches are numerous rakers consisting of single, 

 upright, needle-like spines (cf. Matsubara and Iwai, 1952). 



There are no teeth on the hypobranchials, basibranchials, or tongue. 



Sensory canals of head and associated bones. — The infraorbital 

 canal is complete and joins the supraorbital canal between the frontal 

 and pterotic as usual. The lacrimal is a long bone that does not overlap 

 the maxillary except far forward. It has no serrations but has the 

 usual three canal exits along the lower surface. The first circumorbital 

 is essentially a continuation of the lacrimal. The second circumorbital 

 bears a very large subocular shelf that extends somewhat forward as 

 weU as somewhat back of its canal-bearing portion. Above the second 

 circumorbital are 11 bony half rings (the medial halves) that carry 



280-835—68 3 



