1. MUGIL. 411 



from passing through the gill-openings, these fishes have the organs 

 of the pharynx modified into a filteriiig apparatus. These fishes take 

 in a quantity of sand or mud, and after having worked it for some 

 time between the phar}Tigcal bones, they eject the roughest and 

 indigestible portion of it. The upper pharyngeals have a rather 

 irregiilar form ; they are slightly arched, the convexity being di- 

 rected towards the pharjmgeal cavity, tapering anteriorly and broad 

 posteriorly. They are coated with a thick soft membrane, which 

 reaches far beyond the margin of the bone, at least on its interior 

 posterior portion ; this membrane is studded aU over with minute 

 horny ciha. The pharyngeal bone rests upon a large fatty mass, 

 giving it a considerable degree of elasticity. There is a very large 

 venous sinus between the anterior jjortion of the pharyngeal and the 

 basal portion of the branchial arches. Another mass of fat, of ellip- 

 tical form, occupies the middle of the roof of the pharjTix, between 

 the two pharyngeal bones. 



Each branchial arch is provided on each side, in its whole length, 

 with a series of closely-set lamella) (rakers), which arc laterally bent 

 do-WTiwards, each series closely fitting to the series of the adjoining 

 arch ; they constitute together a sieve admirably adapted to permit 

 a transit for the water, retaining at the same time every other sub- 

 stance in the cavity of the pharynx. 



The lower pharyngeal bones are elongate, crescent-shaped, and 

 broader posteriorly than anteriorly. Their inner surface is concave, 

 corresponding to the convexity of the upper pharyngeals, and pro- 

 vided with a single series of lamcllaj, similar to those of the branchial 

 arches, but reaching across the bone from one margin to the other. 



Internal parts. — The lower portion of the oesophagus is pro\ided 

 with numerous long thread-like papUlae, and continued into the 

 oblong-ovoid membranaceous caecal portion of the stomach, the 

 mucosa of which forms several longitudinal folds. The second 

 portion of the stomach reminds one of the stomach of birds ; it 

 communicates laterally with the other portion, is globular, and 

 surrounded by an exceedingly strong muscle. This muscle is not 

 divided into two, as in birds, but of equal thickness in the whole 

 circumference of the stomach, all the muscular fasciculi being cir- 

 cularly arranged. The internal cavity of this stomach is rather 

 small, and coated with a tough epithelium, longitudinal folds running 

 from the entrance-opening to the pyloric, which is situated opposite 

 to the other. Where the epithelium ceases, there commences the 

 mucous membrane of the intestine with a low circular valve, thus 

 forming a sort of pylorus. There are five rather short pyloric ap- 

 pendages. The intestines make a great number of circumvolutions ; 

 they are seven feet long in a specimen thirteen inches in length. 

 The peritoneal folds are filled with innumerable small lobes of fat, 

 enveloping and covering the intestinal tract. The peritoneum, is 

 black. The liver is of moderate size, its greater portion being situ- 

 ated on the left side ; gall-bladder large, free, and not imbedded in 

 the substance of the liver. The ovaries are large and long, con- 

 taining an exceedingly large number of apparently nearly mature 



