SYSTEMATIC CATALOGUE OF FISHES. 307 



regarding a phenomenon so easily investigated in most parts of the world; and that a con- 

 spicuous specialized drunmiing muscle should have been either overlooked or ignored by 

 ichthyologists. 



For several years, as opportimity was afforded, I have been studying the peculiar drum- 

 ming sounds made by those fishes in which this function is so strikingly developed that it has 

 determined the family name, the inquiries being in continuation of some observations and 

 experiments on the squeteague {Cynoscion regalis) carried on by Professor R. W. Tower, at 

 Woods Hole, in 1901 and 1902, and noted by me in the Report of the U. S. Fish Commissioner 

 for 1902 (page 137). 



The drumming act has been more thoroughly studied in the squeteague than in any other 

 scisenid species; and the facts regarding it, as determined by Professor Tower, may here be 

 repeated substantially as stated by me in 1902 (l. c), but in somewhat greater detail: 



1. There is in the squeteague a special drumming muscle, lying between the abdominal 

 muscles and the peritoneum and extending the entire length of the abdomen on either side of 

 the median line, the muscles of the two sides being united dorsally by a strong aponeurosis. 

 The muscle is of a decided red color, in sharp contrast to the pale muscles of the abdominal 

 parietes, and the fibers are very short, running at right angles to the long axis of the muscle. 



2. The muscle, with the aponeurosis, is in close relation with the large air-bladder, and by 

 its rapid contractions produces a drumming sound, with the aid of the tense air-bladder, which 

 acts as a resonator. Experimentally, the removal of the air-bladder or the section of the 

 nerves supplying the muscle abolishes the sound; if a removed air-bladder is restored to its 

 place the drumming is resumed; and the substitution for a removed air-bladder of any hollow, 

 thin-walled vessel of suitable size permits the resumption of drumming when the special 

 muscle is stimulated. 



3. The muscle exists only in the males, and only the males are able to make a drumming 

 sound. 



It is probable the drumming mechanism and function as existing in the squeteagues are 

 typical of a majority of the genera of Scisnida;; but there are some interesting variations in 

 the limited number of genera which I have been able to examine in the field and laboratory. 

 Thus in the croaker {Micropogon undulatus) the special drumming muscle is present in both 

 male and female, and both sexes make the drumming sound; while in the so-called king-fishes 

 or whitings {Menticirrhus) the drumming muscle and air-bladder are absent in both sexes and 

 no drumming sounds are made. The seven commonest genera of drum-fishes found along the 

 Atlantic coast may be thus classified with reference to the drumming fimction: 

 i. Drumming muscle present in both male and female, and drumming sound made by both 



sexes • Micropogon. 



ii. Drumming muscle present only in male, and drumming soimd produced only by the male. 



Pognnias. Scioenops, Cynoscion, Leiostomus, Bairdiella. 



Hi. Drumming muscle absent in both male and female, and no drumming sound produced by 



either sex Menticirrhus. 



The fishes of this family in North CaroUna are in the aggregate more valuable 

 than all the other salt-water fishes combined. The annual catch exceeds 

 7,000,000 pounds and is worth over $225,000. 



The most important anatomical characters of this family are as follows: 

 Body elongate, variously compressed, covered with scales which are usually 

 thin ctenoid; head large, scaly, bones cavernous; mouth large or small, teeth in 

 one or more series on jaws, no teeth on vomer, palatals, pterygoids or tongue; 

 barbels sometimes present on chin; maxillary bone without supplemental bone, 

 slipping under edge of usually broad preorbital; premaxillaries protractile; 

 gill-membranes not united; and free from isthmus, branchiostegals 7.; pseudo- 

 branchice usually present and large; posterior margin of opercle with 2 flat 



