182 SCANDINAVIAN FISHES 



6 specimens (2 %) had nri extniordinarily short head, 



6 

 10 



(2 %) Avere veiy nearly short-headed, 



(8',., 96) hnd the ridges and protul)eran- 

 ces of the head very strongly 

 marked (transition to Coitus 

 hiihaJis)i 



(I'A, %) had tlie ridges and protul)eran- 

 ces of the head extremely little 

 developed and also covered by 

 the skin (transition to Coffus 

 ffohio), 



(' !(, %) had very short preopercular spi- 

 nes, almost covered by the skin 

 (transition to Cottus gohio). 



7 specimens (2*/2 %) had the longest preoi)ercnlar 



spine l>ranched at the tip or 

 furnished Avith small lateral spi- 

 nes (transition to Coffus diccrai(s 

 and reiifraJis), 

 {] ,, (2 %) had an irregular arrangement of 



ridges on the head. 

 If we MOW endeavour to find an explanation n[ 

 the cause of similar changes of form, we ol)tain the 

 clearest indications, here, as in other cases, by follow- 

 ing the course of the chaiiiies due to aoe aiid iuAcsti- 

 gating the expression of the external sexual differences, 

 Avhile this species also affords singular proof of the 

 appearance of different chai-acters in different geogra- 

 phical environments. The following table is calculated 

 to give information on these points: 



Cottus scorpitis. 



Length of the body csjiresseil in milli metres 



„ „ „ head in % of the length of the hndy 



„ „ ,, maxillai'v bones ,, ,, ,, ,, ,, 



,, „ .. lower jaw ,, „ „ ,, .. .. ,. ,, 



LonsritHdinnl diameter of the eyes ,. ., ,, ,, ,, ,, ,, „ 



lireadth of the interorbital spaec ., ,. ., ,, ,, „ „ „ 



Least depth of the tail „ „ ,, ,, „ „ „ „ 



Distance between the first dorsal fin and the 



tip of the snout „ „ ,, „ „ „ „ „ 



Distanee between the beginning of the first 



dorsal fin and that of the seeond „ ,, „ „ „ „ „ ,, 



Base of the second dorsal tin „ „ ,, ,, ,. ,, „ „ 



„ „ „ anal fin „ „ „ „ „ „ „ „ 



Length of the ventral fins „ ,, ,, „ „ ,, „ ,, 



Distance between the insertion of the vent- 

 ral fins and the beginning of the anal fin „ ,, „ „ „ „ „ „ 



Distance between the beginning of the anal 



fin and the tip of the snout „ „ „ ,, ,, 



Length of the pectoral fins from the upper 



end of the base „ ,, ,, „ ,, ,, ,. ,, 



Length of the pectoral fins from the lower 



end of the base ,, ., .. ,. , ,, 



Length of the maxillary bones in % of the base of the second dorsal fin... 



„ „ ,, lower jaw „ „ „ „ „ „ „ „ ,, „ ... 



Least depth of the tail ,, ,, ,. ,. ., ,, ,, anal tin 



,, „ ,, ,, „ in % of the distance between the insertion of the 

 ventral fins and the beginning of the anal fin 



Longest ray of the first dorsal fin in % of the distance between the begin- 

 ning of the first dorsal fiu and that of the second 



o ... 



St? 



o 2. 









Bolusllin, 

 Julv, 1835. 



Greenland, 



Ivigtut Aug. 

 1883. "^ 



Cottus platij- 

 cephnhis. 



The winter- 

 quarters of 

 the -Vciia,' 

 18711. 



19/ 



96.0 

 33.5 



12.9 



16.1 



7.G 

 3.7 

 5.3 



30.0 



20.0 

 24.0 



17.6 



16 



61.2 



20, 



30.1 

 52.4 

 65.8 

 30.2 



20.7 



51.11 



149 

 33.5 



13.4 



16.6 



7.4 



4.1 



4.7 



30.2 



20.8 

 26.8 



17.4 



18. 



25.2 



51.3 



21.4 



31.5 

 50.0 

 59.2 



27.0 



18.6 



55.0 



9 

 189 

 36.0 



14,8 



18.0 



6.9 

 4.2 

 5.5 



80.8 



20. i) 

 20.4 

 19. G 



17.4 



26.4 

 53.6 

 22. 



31.2 



56.0 

 68.0 

 28.4 



21.0 



48.1 



& 

 189 

 36.0 



14.3 



18.0 



7.4 

 4.7 



6.1 



31.7 



18.6 



26, 



19.7 



18.2 



25.7 



54.2 



21.7 



30.0 

 54.0 

 68.0 

 30.8 



22.0 



9 

 201 

 32.8 



14.6 



17.1 



5.2 



4.4 

 4.9 



32.1 



21.7 



25.2 



19.4 

 15.9 



28.6 

 54.7 



19.9 



30 



58.1 



67.9 



25.6 



17.4 



53. r, 



204 

 32.6 



13.3 



16.4 



5.4 



4.7 



5.4 



29.9 



21 

 26.0 

 18.1 

 20.8 



25.0 



52.4 



22.5 



30.4 

 50.9 

 63.2 



30.0 



21.6 



201 

 34.3 

 12.9 



16.1 



r. I 



7-4 

 3.9' 

 5.4 



30.3 



19.2 



27.6 



18.9 



9 

 227 

 34.3 



14.5 

 16.7 



6.1 



4.4 



30.6 



20.7 

 27.3 



17.7 



20.3J 15.0 



25.2; 29.6 



53.S 54.G 



22.0; 21.1 



31.3 30.8 



46.8 53.2 



58.5! 61.1 



29.0 29.5 



21.7' 17.G 



72.5' 56.4 



9 

 299 

 33.8 



14.7 



16.7 



5.0 



4.3 



5.7 



32.1 



23.7 

 26.7 

 17.0 

 16.7 



26.7 



50.8 



21.4 



32.1 

 55.0 

 62.6 

 33.3 



21.2 



59.1 



9 

 310 

 32.9 



14.7 

 17.3 



5.1 



4.4 



5.5 



23.2 

 27.4 



17.7 

 16.4 



54.8 



21.G 



30.0 

 53.5 

 62.3 

 30.9 



20.0 



58.3 



& 

 211 

 31.5 



12.3 

 19.2 



4.3 



7.1 



3.9 



30.0 



20.5 

 28.9 

 24.6 

 19.9 



27.5 



52.1 



26.0 



37.4 

 42.G 

 66.6 



15.G 



14.0 

 52.0 



255 

 30.6 

 12.1 



18.8 

 3.9 

 7.8 

 4.3 



27.8 



22.3 

 25.5 



22.7 



18,4 



28.2 

 52.3 

 23.9 



36.1 



47.7 

 73.9 

 19.0 



15.2 



i 

 54.4 



