302 Mr. P. Schmidt on the 



the species of Hippoglossoides as described by different writers, 

 and shows that the differences are very uncertain. 



We see in Table I. that the number of rays in the dorsal 

 and anal fins of Hippoglossoides robustus (D. 76, A. 60), 

 H. dubius (D. 85, A. 67), and H. katakurce (D. 80, A. 69) 

 lies between the limits of variation of the number of rays in 

 H. elassodon {Y). 77-87, A. 59-67), or is very near to these, 

 and only in II hamiltoni (D. 72, A. 56) this number differs 

 slightly. The depth of the body seems to be very different 

 in Hippoglossoides dubius (33*3 °/ of the total length), but 

 it is possible that the American ichthyologists have measured 

 the length of the body from the tip of the snout to the base of 

 the caudal, as measurements to the tip of the caudal, taken on 

 the figures (Jordan & Gilbert, 1899, pi. Ixxxiv. ; Jordan & 

 Goss, 1889, pi. ii. fig. 5) have given for Hippoglossoides 

 hamiltoni 328 % an ^ f° r -^ elassodon 35'8 °/ of the total 

 length — i. e., nearly the same as in Hippoglossoides dubius. 



A more marked difference seems to lie in the diameter of 

 the upper eye ; but everybody who has measured flat-fishes 

 knows that this is the most variable and uncertain measure. 



If we compare now other morphological features, we shall 

 see that they give no good characters for separation of the 

 five Pacific species of Hippoglossoides. 



The teeth in the jaws in all the species are in a single 

 series. In Hippoglossoides elassodon they are, according to 

 Jordan & Gilbert (1880, p. 278), " in the upper jaw . . . small 

 conical, not very sharp . . . somewhat larger in front than on 

 the sides and also more widely set/' " lower jaw with a single 

 series of rather close-set teeth similar to those in the upper 

 jaw or slightly larger; those on the sides smaller than the 

 anterior teeth ; number of the teeth about 25 t^j ." In Hippo- 

 glossoides robustus, Gill & Town., after Jordan & Evermann* 

 (1898, p. 2616), " teeth of the single row mostly separated 

 from each other by intervals equal to width of teeth, curved 

 inward and uniform on the sides ; toward front 4 or 5 

 enlarged preceded by two smaller, leaving the middle toothless; 

 in the lower jaw of nearly uniform size and inclining back- 

 ward." In Hippoglossoides hamiltoni, after Jordan & Gilbert 

 (1899, p. 489), " teeth acute, in a single series in each jaw, 

 all except the anterior teeth in each jaw short. At the 

 symphysis of lower jaw the teeth are longer and directed 

 inward, while in the anterior end of each premaxillary the 



* I have not seen the original description of Gill & Townsend, as this 

 volume of True. Wash. Biol. Soc. is wanting in our library. 



