54 U.S. NATIONAL MUSEUM BULLETIN 284 



spondylus transversus (Springer, 1957), the only nonblenniid reported 

 to possess such an arrangement. 



The number of epipleurals ranges from eight or nine in Xiphasia to 

 31 or 32 in Lophalticus. The number is fairly variable within genera, 

 but only sUghtly so within a species, wherein a variation of four 

 epipleurals is uncommon. In blenniids the differentiation between the 

 anterior two epipleurals and the pleurals is not always clear. In 

 EcseniuSf uniquely, the first two epipleurals articulate with well- 

 developed cuplike parapophyses similar to, although smaller than, 

 those with which the pleurals of the third and fourth vertebrae artic- 

 ulate. These epipleurals appear, serially at least, to be typical ribs 

 (in percoids the pleurals are usually considered to begin on the third 

 vertebra, the epipleurals on the first — Goshne, pers. comm.). The 

 third through fifth epipleurals of Ecsenius also are modified uniquely in 

 that they develop a flattened process ventrally where they articulate 

 with the pleurals. Above this process the epipleural bends up toward 

 the neural arch process to which it is ligamentously attached (the 

 bend is apparently an ossification of the attaching ligament and is 

 not differentiated from the remainder of the epipleural). Variably 

 there is a slight, irregular extension arising from the epipleurals above 

 the flattened process mentioned above (apparently an ossification in 

 the vertical transverse septum). The third epipleural on each side of 

 one of the specimens of Stanulus seychellensis also had a dorsal fork 

 that appeared to be an ossification of a portion of the ligament at- 

 taching the epipleural to the neural arch process. 



In the Blenniinae the pleurals extend from the third to the ninth 

 through twelfth vertebrae, depending on the species. There is occa- 

 sionally a variation of one vertebra as to which vertebra the last 

 pleural attaches. The terminal pleurals may be on the terminal pre- 

 caudal vertebra or on the first caudal vertebra, usually constant 

 within a species. In the Nemophidinae the pleurals extend from the 

 third or fourth (rarely the fourth) vertebra to the twelth through six- 

 teenth vertebra. The last pleural may be on the penultimate or ul- 

 timate precaudal vertebra, or on the first caudal vertebra. There 

 seems to be relatively more intraspecific variation in the position of 

 the terminal ribs with regard to which vertebra they attach than is 

 found in the Blenniinae. 



Caudal fin. — Gosline (1961) defined the most primitive perciform 

 caudal skeleton as follows: 



(a) 15 branched caudal rays; (b) 3 epurals; (c) 2 independent uroneural ossi- 

 fications (each uroneural is actually a paired element) ; (d) urostyle with a single 

 ossification; (e) 6 independent hypurals; and (5) haemal arches of the two verte- 

 brae ahead of the urostylar vertebra separate from their centra, i.e., autogenous. 



Goshne (pers. comm.) has accepted Nybelin's (1963) modification 

 of the terminology used by Goshne (1961), and so the ventrahnost of 



