46 



PROCEEDINGS OF THE NATIONAL MUSEUM 



for such musculature, usually are missing; however, in Prolatilus 

 (fig. 9), a very generalized genus of the notothenioid family Paraper- 

 cidae, the usual percoid condition is retained; furthermore, as in the 

 percoids, the supratemporal commissure is incomplete, ending blindly 

 over the musculature. 



Generally, in the Blennioidei, the supratemporal commissure is 

 complete. In such fishes as most notothenioids, all congrogadoids, 

 trachinids, and certain tropical blennies of the families Triptery- 

 giidae (Rosenblatt, 1957, unpubl. Ph.D. dissertation) and Clinidae, 

 the supratemporal canal runs up on each side through the lateral 

 and medial extrascapulars and then crosses the midline in a mem- 

 branous tube; however, in the "uranoscopoid families," in most 

 tropical blennies, and in all the zoarceoids, the medial extrascapular 

 appears to have fused with the parietal. 



Certain tropical blennies and zoarceoids have secondarily developed 

 crests on the skull; e.g., a median crest along the frontals. Such 

 crests, however, are for the attachment of jaw musculature, not body 

 musculature (Makushok, 1958, p. 51). 



Even though a supraoccipital crest rarely occurs on the dorsal 

 surface of the skull in the Blennioidei, a small crest may be retained 

 on the posterior surface. In the zoarceoids, with the single exception 

 (known to me) of Cryptacanthodes (Makushok, 1961a, fig. 3), even 

 this section of the crest is lost. 



Sphenoid region of the cranium (fig. 10). — So far as the 

 differentiation of lineages among the Blennioidei is concerned, the 

 sphenoid region of the cranium seems to be one of the most diag- 

 nostic parts of the whole fish. The features of importance here are 

 the basisphenoid and the postorbital bar. 



>&>, 



Figure 10. — Diagrammatic cross-section of cranium, looking toward rear, at level of front 

 of basisphenoid: a, Prolatilus jugularis; b, Bat hy master signatus. (Vertical hatching = cut 

 areas, stippling=cranial cavity, bs = basisphenoid, fr=frontal, pl = pleurosphenoid, po = 

 prootic, ps = parasphenoid, sp = sphenotic.) 



The basisphenoid is a bone that has been lost repeatedly in fishes. 

 In general, this loss seems to be associated with the development 

 of a broad, depressed cranium (see p. 21). Thus, among the noto- 



