GREGORY: FISH SKULLS 



253 



The otoliths of the family Sciaenid^, according to Frost {1927b, p. 303), are highly 

 specialized, and the sagitta is often of great size and unusually ponderous. Possibly this 

 may be connected with the well-known habit of these fishes of making sounds while in the 

 water. 



The main otolith (sagitta) of Cynoscion nebulosus, as figured by Frost (1927^, p. 303), 

 is closely related in form to that of Aplodinotus grunniens of the same family. This in turn 

 is a very much isolated type which according to Frost has certain features resembling the 

 otoliths of the Berycidae. 



Gerrids. — In Gerres, type of the Gerridae, the mouth (Fig. 126) is extremely protrusile 

 and is withdrawn beneath an overhanging ridge formed by the maxilla and the lacrymal. 



Nexilosus albemarfeus 



Fig. 127. Nexilosus albemarleus. 



Boulenger (1910, p. 663) notes that the "premaxillary emits an upward lateral process," 

 and that the lower pharyngeal bones are usually large and more or less completely coalesced 

 as in a number of other families of percomorphs. Tate Regan (1913a, pp. 121-122) notes 

 that in this family the mouth is "very protractile, the long prsemaxillary pedicels lying in a 

 groove or chamber formed by the bifurcation of the occipital crest; maxillary variable in 

 form, but always with the anterior edge curved more or less in the shape of an S; distal 

 extremity exposed; no supramaxillary; palate toothless." He regards them as being "closely 

 related to the Lutianidae." As the body in Gerres is deep, the back of the skull rises steeply 

 into the very high supraoccipital. 



The main otolith (sagitta) of Gerres rhombeus, as figured by Frost {1927b, p. 300), 

 rather closely resembles that of Lutianus chirtah. Frost states that it resembles that of 

 Perca, although differing in certain features. 



