THE CHiETOGNATHA. 77 



if SO, do tliey range also to the surface ? The answer for hamata appears to be, that 

 tlicy rise higher, but stop short of the surface ; zetesios apparently follows the same 

 habit. Of course w^here, as in the subarctic region, the species is epiplanktonic, the young 

 are also ei^iplanktonic. 



The materials are now to hand for a faii'ly complete idea of the distribution of 

 K. hamata in the Atlantic. As an ei)iplanktoDic and mesoplanktonic form it ranges 

 from 81° N. (Eomer and Schaudinn) over the North Atlantic, from Greenland and the 

 Labrador Current in the west to Spitzbergen and Lofoten in the east, occasional drifted 

 speciinens reaching along the Norwegian coast into the Baltic. In the Faeroe Channel 

 A\ith comparatively high surface-isotherms, it shows a preference for the mesoplankton, 

 although also occurring less plentifully in the epiplankton *. Passing southwards — in 

 the Bay of Biscay it was purely mesoplanktonic. In the South Equatorial Current the 

 same holds good ; only young specimens were obtained by the ' National,' and only by the 

 closing-net at considerable depths f . Still further south, young specimens were obtained 

 from a depth not greater than 38 fathoms, at 40° S., by Dr. Schott and Captain Bruhn + ; 

 in other words, the species rises nearer to the surface at high latitudes with a lower and 

 more suitable surface isotherm. Lastly, I am glad to be able to complete the series by a 

 weU-preserved and unmistakable specimen captured at or close to the surface by my 

 friend Mr. Vallentin at the Falkland Islands, well within a subantarctic district. 



Krohnia hamata, Moebius, var. (PI. 6. figs. 47-49.) 



Among the hamata were a few specimens which could not be quite reconciled with all 

 the characters of Moebius's species, although probably only a variety. There were tAvo 

 well-preserved specimens of 23 and 12 mm., the smaller serving to connect with some 

 yet smaller larva?. They differ from hamata in the possession of a stouter body, with a 

 less marked taper, of somewhat more curved jaws which seem longer in comparison 

 with the head ; the tips of the jaws are longer and only slightly bent. Fins similar in 

 both. 



The specimen figured (30 e, 23 mm. long) exhibited the characters thus described ; 

 there were also heads and damaged specimens from some other hauls, of Avhich at any 

 rate the jaws and teeth showed the same or an iutermediate variation from hauiata. So 

 likewise did the five small specimens in the table ; these were further characterized by 

 a ferocious-looking sagination of the jaws : a similar sagination has been described by 

 Strodtmann in some young specimens of hamata, which I can confirm from Faeroe 

 Channel material. The saginate jaws are the more ventral (older). The 12 mm. 

 specimen seemed to suggest that the ultimately smooth outline of the jaAV was attained 

 by a filling-up of the spaces between the saw-teeth. 



The occurrences of this variety have been reckoned as hamata in the previous calcu- 

 lations, in the notes on general distribution (p. 81), and in the diagram (PI. 7). 



* The observations on which this statement is based have not yet been published, 

 t 0. Steinhaus : op. cit. supra, p. 34. 

 i O. Steinhaus : op. cit. supra, p. 47. 



