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varying race-character; for also the long rough dab (Hippoglossoides platessoides) 

 seems to grow larger on the shores of Iceland and Greenland, and has their a 

 greater number of rays in the median fins, than it has on our shores; it seems also 

 as if the transition from the pelagic stage to the bottom stage occurs at a consider- 

 ably greater length among the large races than among the small ones, to judge 

 from the specimens lying before me from Norway and Greenland. One specimen 

 from Greenland, So 11 "" Long, has thus, as yet, no real rays in the pectorals, while 

 specimens from Norway, as Long as 27, ; ,""" (see Bg. 19, plate II), have got such; 

 moreover they have adopted the more longish form which makes them more Like 

 the adult fish and more different from the peculiarly broad (rather tall) pelagic 

 young ones with their particularly projecting stomach-region and theconcave profile 

 of their heads. (See plate 11, 6g. 18. "i By the two last-mentioned characters, as 

 also by the peculiar form of its mouth, the Long rough dab distinguishes itself 

 fi'oin the genus Pleuronectes ami approaches the large-mouthed flat-fishes, especially 

 the species of Hippoglossus, to which this fish, evidently, is nearly related. The 

 species of Hippoglossus and the long rough <hil> have also that peculiarity in com- 

 mon that the pelagic young ones become large before they take the form of the 

 grown-up fish ami the bottom stage commences. Plate II, tig. 20, represents 

 the outlines of a Hippoglossus vulgaris, .",2""" long, from Christianssand (the spe- 

 cimen mentioned by Collet in Norges Fiske and by LMjeborg in »Sveriges och 



Norges Fiskar ), and plate II, lig 21, a 51 ] long Hippoglossus hippoglossoides 



from Greenland. Both arc furnished with true rays in the median fins, but 

 the specimen fig. 21 has scarcely as yet got the whole number, and it was 

 rather badly preserved, so that the rays could not be counted. — The pectorals 

 arc quite larval in both, and both fish must he supposed to have a long time 

 to wait before the pelagic stage is over, particularly the Norwegian specimen, 

 whose left eye has just commenced its wandering; for the rest the fish is syme- 

 trical. The number of rays is, in its dorsal (in c. 104, in its anal fin 88, in 

 its caudal fin 22, which agrees very well with the European halibut; the num- 

 ber of rays in tin' anal fin, however, seems to he somewhat greater than that 

 stated by TMjeborg with respect to this fish, and approaches very much the 

 number in Pleuronectes cynoglossus, with whose number of rays in the median 

 fins the number of rays in this young fish also agrees very nearly. Yet there 

 is no doubt that it must he classed among the- large-mouthed fiat-fishes: more- 

 over it has a row of spines or spikes down the operculum, and a few scattered 

 spines behind this row suggested in plate II, fig. 20), a character which makes 

 it more different from the Pleuronectes-graup and approaches it to the genus 

 Rhombus, to which, we know, the Hippoglossus is not so very distantly related. 

 Slight pigment-spots may he traced in the figure at the places indicated. 



In the Greenland form (plate 11, lig. 21) no spines could he discovered. 

 On account of the smaller number of rays in iis fins, c. 70 in the anal tin 

 and c. 19 in the caudal fin (the rays in the dorsal fins could not he counted 

 with certainty owing to its being so badly preserved), I have considered it a 

 specimen of a species of halibut living in Greenland, viz. Hippoglossus lui>/>'> 

 glossoides. It was slightly pigmented and had, particularly, large spots along 



