corn II I )s. 



THE ALPINE BULLHEAD (s\v. nEHcsiMrAN"). 



COTTUS POBCILOPUS. 



FiR. 50. 



Head (tnucij as nt the jircccdiiK/ s/iccirs, Iml llic n/)/ifninisf /in'ojjcrralar spnie not so carn'd, sometimes almost 

 strali/lif. iJisfaiice l>efireeii the aiud Jin ami the fi/i nf llic simat at most 47'^/., % of the leiif/tli of the hoilij, and 

 the lei/(/th of the base of this fin more than '><) %'' of lliis distance. Length of the innermost ra;/ of the rentral 

 tins less than htdf or rrrn than a third of the lenf/th of the fns. ddl-openinejs as in the jireredinfj species, 



and idso the relafire Icnffh of the jan's. 



Fig. 50. Coitus jioecilopiis from Motala River, 1st Oet., 18G1, C. Sun'Devai.l. Natural size. 



B. hr. G'-; D. 7 1. 8'' 17M. 18; .1. 14'; P. \?, 1. 14; V. 'v 

 V. x+l — 9 + ,r; L. tat. s:rpiss. imperf. 



'^yn. Cottus poecilopus, Heck., Ann. Wion. llus., II (18oG), p. 

 145, tab. 8, fig. 1 et 2; SUND., Ofvers. Vet.-Akad. Forh. 

 1851, p. 185; NiLS.s., iSlcand. Fn., Fislc.. p. G7; Heck., 

 Kn., Sussicasscrf. Oesterr., p. 31; Gthr, Cat. Brit. 3/iis., 

 Fisli., vol. II, p. 157; Jeitt., Arch. p. 1. Zoologia, vol. 

 I, p. 175; LiNDSTR., Gotl. Fisk., 1. c, p. 14 (sep.); C'OLI,., 

 Forli. Vid. Selsk. Cliniia 1874, Till.Tgsh., p. 24; 1870, 

 No. 1, p. 12; Ol.ssoN, Ofvers. Vet.-Akad. Furli. 1875, No. 

 .'5, p. 129: Malm, Gtigs, Boli. Fn.. :is8: Lu.i.j., .S'l'., Xi>i;j. 

 Fistcar, vol. I, p. 131. 

 Cottus gobio, Dav, Fish. G:t Brit., Irel., vol. I. fab. XIX, 

 lig. 2. 



Ol/s. None of the Scandinavian species of this genus has been 

 so variously estimated, and justly so, as the Alpine Bullhead in its 

 relation to the preceding one. Most of the characters given by 

 Heckel can scarcely be retained, and only one of them — that which 

 consists in the length of the innermost ray of the ventral fins, a point 

 not touched upon by Heckel in liis latest work — may be regarded 

 as an unmistakable mark of the species, as far as we know it up to 



the present. Furthermore, JIai.m, Day, Benecke and MuBlus and 

 Heincke still maintain the opinion that the two species are not di- 

 stinct. On e.xamim'ng the different relations of age and sex in both 

 species (see the appended table), we also find that their relative po- 

 sitions in the chain of development indicate a common origin of a 

 period not far removed from the present. In all the respects in which 

 Cottus poecilopus differs from Cottus ijobio, it exhibits the juvenile 

 or the male characters of the latter, or both combined. This appears 

 most clearly from a comparison between the length of the ventral 

 fins and the distance from the anal fin to the tip of the snout, for 

 the relative size of the fins gradually diminishes witli age — pro- 

 vided that this be expressed by the increase in the length of llie 

 body — and is greatest in the males and greater in (.'ottits poeci- 

 lopus than in Cottus gohio. It is also strange that, while in ('otitis 

 gobio the females are more common than the males, the contrary is 

 the case iu Cottus poecilopus, at least in the collections of the Royal 

 Museum. Again, in the south and east of Sweden at least, no fixed 

 limits can be set to the range of either species: Su.VDEVAl.r, found 

 both in the islaiid-bilt of Stockholm, they occur together in Mo- 

 tala River, and Lin'DSTrom assigns them both to Gothland, even though 

 it be to different lakes. It is, therefore, easy to understand how 

 confusion has often arisen in the specific and sexual differences of 

 the two species. The following comparative table may afford more 

 minute information on this point. 



" LlLUEBORG, 1. C. 



* At least 53 % in the specimens we have measured. 

 ' Sometimes 5, according to Heckel. 

 •^ Or 9, according to Heckel. 

 " Or 10, according to Heckel. 

 •'' Or 13. according to Heckel. 



