302 Mr. P. Schmi.lt on the 



ihc s\)ec\QSon/ippogIossoi\h's as described hy different writers, 

 and shows that tlie ditieri'iiccs are very uncertain. 



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

 and anal fins of lUppoqlossoides robustus (D. 7G, A. 60), 

 //. duhius (D. 85, A. 67), and //. katakurce (D. 80, A. 69) 

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

 Ji. elassodon (1). 71-Sl, A. 59-67), or is very near to these, 

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

 slightly. The de|)th of the boiiy seems to be very different 

 in llippofjlossoides duhius (3o"3 °/q 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 Hippoglossnidis 

 hamiltoni 328 °/q and for II. elassodon .'35'8 °/q of the total 

 length — i. e., nearly the same as in Ilippoglossuides duhius. 



A more maiked 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 mor])hological features, we shall 

 see that they give no good characters for separation of the 

 five Paeific species of IIip2)oyhssoides. 



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

 series. In Uippoglossoides elassodon tiiey are, according to 

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

 conical, not very sharp . . . somewhat larger in fiont 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 ||i^." ^^ Hippo- 

 (jJossoides rohustus. 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 & Gilbeit 

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

 {ill 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 ori^al deecription of Gill & Townsend, as this 

 volume of Proc. Wash. Biol. Sec. is wanting in our library. 



