no. 3647 PERCIFORM FISHES — GOSLINE 49 



Regan (1913, p. 141) states that the trichonotid (sensu lato) Bembrops 

 also has three actinosts, but I find four in two specimens identified as 

 B. gobioides. 



Inasmuch as the possibility for pectoral rotation has been largely 

 lost in most of the Blennioidei, the differentiation between the upper- 

 most ray articulation and that of the lower rays diminishes. Indeed, 

 several of the upper pectoral rays usually move up to an articulation 

 on the scapula along with the uppermost. 



The tropical blennies, with the batrachoids and lophioids (Starks, 

 1930), are unique among teleosts in that they have developed second- 

 arily an ability to rotate the fins— but not on the uppermost ray 

 articulating with the scapula as an axis. Except in the Tripterygiidae, 

 the pectoral rays all articulate with separately movable actinosts 

 (fig. lie). (The axis for maximum rotation for such a fin theoretically 

 would lie between the two middle actinosts.) 



The pelvic fins in the Blennioidei, when present, are always in ad- 

 vance of the pectoral bases, though in a few of the generalized forms, 

 like the parapercid Prolatilus, not much so. 



Among the Blennioidei, three things happen to the pelvic fins. 

 One, which seems to have no phylogenetic significance, is that, in 

 elongate fishes, the pelvics tend to dwindle in size and disappear 

 completely. A sequence of this sort can be followed in the nototheni- 

 oid family Trichonotidae (Apocreedia) , in the congrogadoids, and in 

 the zoarceoids (Makushok, 1958). 



Those Blennioidei in which the pelvics are not minute or absent 

 seem to have put them to two rather different uses. In one, represented 

 by the Dactyloscopidae, almost all the Blennioidae, and to some 

 extent the Trachinidae, the two or three outer soft rays are simple, 

 somewhat strengthened, and recurved at their tips, which extend well 

 beyond the membrane between them. Usually such fins are held more 

 or less erect under the body. 



In the other type of development, the pelvic fins are held back flat 

 against the abdomen, but all five rays are retained, none are strength- 

 ened, and the inner are at least somewhat the longest. In this type of 

 development, which occurs in almost all of the the Notothenioidae 

 and in the Leptoscopidae, the pelvics frequently become separated 

 widely from one another. Such fishes must rest with their thoracic 

 areas between the pelvics in direct contact with the substrate. 



The pelvic girdles of the Blennioidei are very varied. The only 

 taxonomically meaningful structural peculiarity that I could find is 

 that mentioned under the Trachinoidae (see p. 59). 



Vertical fins.— The basic dorsal fin arrangement that runs through 

 many of the Blennioidei is a short, anterior spinous dorsal followed 

 by a long, low fin of soft rays. Especially in the eel-shaped forms, 



280-835— 6S i 



