230 



in the East-Greenland specimens to 26.6 — 28.8 % of the total 

 length, the length of the upper jaw to 9.7 — ll.7"/o, and the 

 length of the lower jaw to 12.5 — 14.6%; in the specimens from 

 the Baltic the length of the head amounts to 29 — 33.6 %, the 

 length of the upper jaw to 11.7 — 14.3 ''/o, and the length of the 

 lower jaw to 15.6—16.9 %. Professor F. A. Smitt has in his 

 work: Skandinaviens Fiskar (I, 1892, p. 177) given some mea- 

 surements of 11 C. quadricornis from the Baltic and Vettern, 

 whereby the limits for variation are certainly somewhat extended, 

 but the total impression remains about the same. In these 1 1 

 specimens (total length 73 — 274 mm.) the length of the head 

 amounts namely to 28.2 — 33.2 % , the length of the upper jaw 

 to 10.9—15.3 % and the length of the lower jaw to 14.8—17.5 %. 

 Moreover I find that the tail in the specimens at my 

 disposal from the Baltic is a little less slender; of 

 the total length the minimum height of the tail in 8 adult 

 specimens (179 — 249 mm.) from East-Greenland amounts namely 

 to 3.3 — 3.9%, but in 5 adult specimens (178 — 246 mm.) from 

 the Baltic to 4—4.2 % i). 



Thus the East-Greenland form has not only a shorter upper 

 jaw than the Baltic form, as pointed out by Professor Peters, 

 but also the lower jaw and the whole head are shorter, and 

 moreover the caudal peduncle is lower, at any rate judged by 

 the material at my disposal. But in all other ways they are 

 perfectly in accordance as far as I can see. Also the numbers 

 of rays which Peters considers to be of some importance nearly 



') According to the measurements of Professor Smitt, the minimum height 

 of the tail amounts, in 6 adult specimens (173 — 272 mm.) from the Baltic 

 and Vettern, to 3.8—4.1 "/o of the total length, a fact which substan- 

 tially confirms the correctness of the above stated. On the contrary in a 

 seventh specimen (274 mm.) the percentage was stated to be only 3.6 °/o, 

 but I almost imagine this to be due to a misprint, as S. remarks that 

 in two specimens from the Arctic Sea of Siberia the percentages for the 

 minimum height of the tail, stated to be 3.5—3.6 °/o of the total length, 

 are low compared with the ones in the specimens from the Baltic. 



