132 THE ZOOLOGIST. 



THE PHARYNGEAL TEETH OF FISHES. 

 By Colonel C. E. Shepherd (Indian Army). 



(Continued from vol. xiv. p. 425.) 



In the Gadidcs we have a family that is well furnished with 

 pharyngeal teeth, and may begin with one of the commonest of 

 this family. 



Gadus morrhua. The Cod. 



The first branchial arch has on the outside edge eighteen 

 horny gill-rakers on the cerato- and hypo-branchials, with nine 

 on the epibranchial ; the longest ones, the seventh and eighth of 

 the first series, are about one-half of the depth of the gills just 

 below them. As they progress towards the front of the mouth 

 they gradually dwindle in size till they become rudimentary. 

 The inner side of the first arch and both sides of the second and 

 third arches, and the outer side of the fourth arch, carry teeth 

 bearing tubercles so placed as to fit alternately into each other 

 when the gill-slit is closed. The upper pharyngeal teeth consist 

 of one patch of elongated shape, attached to the end of the 

 second epibranchial, and a roughly quadrilateral shaped plate, 

 but really consisting of two pieces, on the ends of the third 

 and fourth epibranchials on each side. The teeth on these are 

 cardiform, those nearest the cesophagal opening being much 

 stronger than the others. The teeth of the lower pharyngeals 

 are more finely cardiform, but with stronger cardiform teeth 

 on the inner margins, where the two plates of the lower 

 pharyngeals meet in a broad V, although they do not touch 

 each other in the median line. It would not be out of place 

 here to consider the class of food that the pharyngeal teeth of 

 the Cod has to deal with. In the southern part of the North 

 Sea they feed mostly on crustaceans. These were found in 

 83 per cent, of stomachs examined, and consist of Grabs, in- 

 cluding the Hermit-Crab, and Shrimps and Prawn-like animals. 

 Fish were found in 35 per cent., the greater Sand Launce and 

 the young of the Herring, the Sand Dab, and the Whiting, and 

 other fish as well are brought into requisition. Polychjete 



