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TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



lower angle, and a curved and pointed cauda. It differs in the presence of a narrow crest 

 which encloses the front of the ostium, and in the dentations of the ventral rim. Except for 

 these slight modifications, it is essentially the otolith of a Percoid Fish. It is rather more 

 curved in its length than those of the remainder of the Flat-fishes." 



GoBioiDEi (Gobies) 



Most of the gobies are quick-darting little fishes but Eleotris (Fig. 226) is a sizable fish 

 of aggressive, even ferocious looks. In general the gobies are close to the typical percoids 



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Eleotris 



Fig. 226. Eleotris. 



but more specialized in many features, including the close appression of the opposite pelvic 

 fins, which often serve as suckers. The jaws are of the percoid type, with more or less pro- 

 trusile premaxillae and toothless maxillae which are excluded from the gape. The suspen- 

 sorium is prolonged to a point beneath the small orbits, but as the depth beneath the orbits 

 is somewhat less than usual, the lower border of the mandible is directed only moderately 

 upward, even though the snout is short. The small eyes look partly upward. They are 

 guarded posteriorly by a large flange of the dermosphenotic. Due to the subdorsal position 

 of the orbits, the interorbital skull-roof is narrow, while the postorbital roof is wide and flat. 

 The hyomandibular is elongate anteroposteriorly but short vertically, the symplectic stout. 

 Behind it is a fenestra which has doubtless been formed subsequently to the thinning-out 

 of the bone at this point and the strengthening of the surrounding elements under the 

 stresses of the powerful adductor muscles. 



The opercular and subopercular are fairly normal, the preopercular is abbreviated 

 dorsally, the subopercular extends upward and backward so as nearly to exclude the opercu- 

 lar from the border of the opercular slit, as in the gadoids and ophidioids. For further 

 details of skull structure see Tate Regan, 1911c, pages 729-733. 



In the famous mud-skipping goby Periophthalmus (Fig. 228) we view some extra- 



