356 EXPLANATION OP PLATES, 



passage from Munster, wlio says of his Byzenos latipinnatus, that 

 " the intestine seems to have been very full when the fish died. 

 It is more elevated than the other parts of the body. On some 

 places one sees in the interior a black earthy mass in which 

 small pointed bodies appear, which are like small pieces of shiny 

 coal." May not this " black earthy mass," and " pieces of shiny 

 coal," be carbonized vegetable matter, the food of the fish? 



It is unnecessary here to dilate on the afiinities oi Jcmassa, as 

 the subject is discussed in the former paper, already quoted. "We 

 may remark, however, that the full investigation of the Permian 

 species has only the more confirmed our opinion of its close al- 

 liance with the Coal-Measure form (the so-called Climaxodus 

 lingucBformis), and of a certain relationship of both to Myliobates 

 and Zygohates. 



We may also state that Janassa is more closely related to 

 Petalodus than was at first thought ; for we now find that the 

 latter genus is provided with both symmetrical and oblique teeth ; 

 so that it is quite probable that they may be found to be arranged 

 in much the same manner as those of Janassa, especially as the 

 former have been found in vertical series, as previously stated. 



EXPLANATION OF PLATES X. & XI. 

 PLATE X. 



Fig. 1. Somewhat enlarged view of a central vertical row of teeth of Ja- 

 nassa bifuminosa, seen in profile, and exhibiting transverse 

 grooves and ridges on the underside : a, under surface, with 

 transverse grooves, of apparently two lateral teeth ; b, a portion 

 of a second lateral tooth. 



Fig. 2. Horizontal row of teeth of the same, a little enlarged : a, anterior 

 scoop-like cutting-margin ; b, crushing-disk ; c, root ; d, first 

 lateral tooth ; e, second ditto ; /, flanking petalodontoid tooth. 



Fio-. 3. Diagram showing the central vertical row of teeth in profile, and 

 to explain their relationship to the jaws : a, supposed upper jaw, 

 6, supposed under jaw ; c, the teeth in use ; d, effete supporting 

 teeth. 



Fig. i. Profile view of a central tooth, somewhat enlarged: a, anterior 

 scoop-like cutting-margin ; 5, crushing-disk ; c^ root. 



