PHANEROSTEON MIRABILE. 1G5 



being more externally placed than the Larger. Scales wanting over by far the greater 

 part of the body, but present as follows : 



(1) A row of median seales in front of the dorsal fin. 



(2) A set of scales median and lateral, clothing the prolongation of the body-axis 

 along the caudal fin. 



(3) A few median scales in front of the lower lobe of the caudal. 



(4) A few rows of small thin scales on the flank, immediately behind the shoulder- 

 girdle. 



1. Phankrosteon mirabilk, Traquair. PI. XXX.V11, figs. 4 — 7. 



1881. Phanerosteon miuabile, E. H. Traquair. Trans. Koy. Soc. Ediub., vol. 



xxx, p. 39, pi. iii, figs. 6 — 8. 

 1891. A. S. Woodward. Cat. Fobs. Fishes Brit. Mus., 



pt. ii, p. 47G. 



Description. — As only one speeies of Pkanerosteon can be accurately defined, it is 

 hardly necessary to give a specific diagnosis. 



The entire length of the most perfect specimen (PI. XXXVII, fig. 4) is four inches, 

 but one in the private collection of the writer measures nearly four inches and a 

 quarter ; the usual proportion of the head to the total length is as one in four, or four 

 and a half. The cranial roof-bones (fig. 6) are granulated with minute tubercles, 

 which occasionally are confluent. The suspensoriurn is oblique, the operculum (o/;.) 

 oblong with rounded off postero-superior angle, and showing traces of fine ridges 

 corresponding with the lines of growth ; the suboperculum (s.op.) is somewhat quadrate- 

 rhomboidal with convex posterior margin. The maxilla (mx.), of the typical Palseonis- 

 coid shape, has its postorbital portion marked with fine ridges running parallel with 

 the posterior and superior margins; the dentary margin and infraorbital process are 

 finely tuberculatecl ; the slender mandible displays on its outer surface numerous 

 delicate ridges obliquely impinging on its upper margin. Teeth were not observable on 

 the original specimens, but they are very distinctly seen on two of those now before me, 

 and are smooth, conical and sharp, with distinct enamel-cap, besides being of two sizes, 

 large and small, the large ones being more internally placed. A few branchiostegal 

 plates (6r.) may be seen under the mandible in most heads, but in no case is the entire 

 series exhibited. The orbit is large, but is, as usual, anteriorly placed, and the ethmoid 

 forms a rounded prominence above the mouth. The bones of the shoulder-girdle 

 present nothing peculiar in their configuration and arrangement. 



On the front part of the flank immediately behind the clavicle are several dorso- 

 ventral bands of scales; the exact number of these bands is difficult to ascertain, though 

 there cannot be less, 1 think, than five. These scales are small, thin, quadrangular, 



