ZOOLOGICAL SOCIETY BULLETIN. 



811 



true fishes the highest number is seven, found 

 only in the lowest sharks, while the characteris- 

 tic number is five. 



The gill of the fish consists of a cartilaginous 

 or bony support, the gill arch, on the outer side 

 of which are arranged the numerous, delicate, 

 thin-walled gill filaments. It is in these fila- 

 ments that the absorption of the oxygen from 

 the water into the blood takes place. The blood 

 flows directly from the heart to the gills by the 

 afferent arteries, one to each gill, and thence 

 passes into very fine vessels in the filaments 

 which have such delicate walls that the blood is 

 brought close to the surface. As the filaments 

 are very numerous a large surface is exposed to 

 the water. After passing through the filaments 

 the blood is taken up by the efferent vessels and 

 thence to the systemic circulation. 



In order to cause the water to flow over the 

 gills certain accessory organs are necessarily in- 

 volved. These are the mouth, oral valve, 

 pharynx, and the gill slits. To prevent food 

 matter from passing out through the gill slits 

 these openings are guarded by the gill-rakers, 

 projections from the inner surface of the gill 

 arch. For the protection of the delicate gills 

 externally the opercular apparatus or gill-flap 

 has been evolved. This ordinarily consists of 

 a series of flat bony plates hinged in such a 

 manner as to allow the water to flow out readily 

 after passing over the gills but closing at once 

 to prevent any injury from the outside. In the 

 sharks there is no such arrangement, each gill 

 slit opening separately to the outside. In the 

 morays the bony plates are reduced and the cov- 

 ering consists mostly of skin. 



The sequence of the breathing movements is 

 as follows: The fish takes in a mouthful of 

 water, closes the mouth or the oral valve, and 

 forces the water backward by muscular action 

 into the pharynx where it passes through the 

 gill slits (the gullet being closed) and over the 

 gill filaments. The water, exhausted of its 

 oxygen, then passes from the gill chamber to the 

 outside by pushing aside the opercular flap. 

 These breathing movements follow each other 

 rhythmically, the rhythm varying according to 

 conditions. Fishes which do not have the oral 

 valve — a fold of skin within the mouth — well 

 developed must needs close the mouth with each 

 respiration, and this is why certain fishes, when 

 caught on a hook in such a manner as to pre- 

 vent the mouth being closed, can be drowned. 



A few fishes have developed special structures 

 which permit them to breath while out of the 

 water. Thus the climbing perch (Anahas 

 scandens) of India has a special modification of 

 the gills and gill chamber for air breathing. 



The lung-fishes have a very vascular air bladder, 

 which is homologous with the lungs of air- 

 breathing vertebrates, and are thus able to 

 breathe air. They inhabit marshes in the trop- 

 ical regions of Australia, Africa and South 

 America, where at certain seasons of the year 

 the water dries up. They are in a dormant 

 condition during this season, however, and only 

 become active with the advent of the rainy sea- 

 son, when the normal gill respiration is resumed 

 to furnish them with more oxygen than can be 

 obtained by the imperfect swim-bladder lung. 



R. C. OSBURN. 



OCEANIC BONITA AND LITTLE TUNNY. 



Two specimens of the Mackerel family recent- 

 ly brought to the Aquarium for identification de- 

 serve mention for the sake of recording their 

 occurrence in this vicinity. These represent the 

 two species of the genus Gymnosarda which are 

 found the world around in warmer seas. 



For one of the species Gymnosarda pelamys, 

 the Oceanic Bonita, there is no local record avail- 

 able and it is not listed in the New Jersey Re- 

 ports. Bean, in his Fishes of New York, men- 

 tions it as a "rare visitor in our waters." The 

 other species is the Little Tunny, sometimes mis- 

 called Albacore {Gymnosarda alleterata). This 

 fish is listed in both the New York and New 

 Jersey reports but no records are given for its 

 actual occurrence in either state. 



For the pleasure of examining these speci- 

 mens we are indebted to Mr. Archibald B. 

 Gwathmey of New York City, who took them 

 witli rod and reel five miles off Manasquan, New 

 Jersey, September 10, 1911. Mr. Gwathmey 

 states that they occurred in large schools. 



APPEAL FOR NEW MEMBERS. 



The Executive Committee will welcome the 

 suggestion of new members, and a blank is en- 

 closed for this purpose. 



The Society is obliged to rely on the dues of 

 members as its chief source of income for the 

 general purposes of the Society, not only for the 

 collections at the Park and the Aquarium, but 

 for the establishment of the new library, and 

 above all, for the game protective work of the 

 Society. 



The Executive Committee wishes to render 

 substantial aid, during the coming year, to the 

 general cause of the conservation of the wild 

 life of the country, and is at present without 

 funds for this purpose. On a membership 

 strong in character and in numbers depends not 

 only the influence of the Society, but in a large 

 measure its financial strength. 



