156 



SCANIMXAVIAN FISHES. 



Fam. C0TT1D.E. 



Body of fill' liijiicnl (Jottus-fonn {flu' hcail thickest and tJie hudij cunicallj/ pointed posteriori i)), witlioat cuirass 



most ofti'i/ naked or partly covered ivitli plates or S2)iiies. Spinous-rayed part of the dorsal fin shorter {with fewer 



rays) than the soft-rayed part. No spinoas rays in the anal fin". By far the yreater part of the rays of the 



pi'ctoral fins, as a rale, simple. Pseudohrancliice prese)it. Vertel^ree generedly more than SO. 



Subfamily C T T I N M. 



Head mure or less completely armed irith sjdnes, hat not cairassed. No air-hladder. 



In the fauna of the northern seas the true Cotti and 

 their nearest relatives are among the most prominent 

 fishes, and their typical form is, therefore, most probably 

 well known to most of my readers. "A head which is large 

 in proportion to the rest of the Ijody, sharply rounded 

 at tlie top and armed witli spines or j)r()tuberances, 

 and which tln'ough the dilatation of the gill-cover and 

 the branchiostegal membrane ma}^ undergo considerable 

 lateral extension and assume a more depressed form; 

 and a body Avhich is rounded and tapers posteriorly 

 in a conical form, is covered l)y a naked or spinous, 

 highly mucous skin, and bears large, rounded tins — 

 these are the general characters which give these fishes 

 an easily recognisable, though uninviting appearance". 

 Many of them, tliough not those forms which are com- 

 mon among us, liave ciHate scales, scattered or even 

 imbricate; Init in far the greater number of cases the 

 above description of EKs'n!r>M holds good. 



The spinous equipment of the head conforms to 

 the same type as in the preceding family, though it is 

 generally more highly develo|)ed. A pair of nasal spi- 

 nes arc; almost always present; and on tlie posterior 

 part of the liead, from the forehead to the end of the 

 occiput, is a (juadrilateral oi' liarp-shaped patch, which 

 is often conc-ivc and is l)ounded at its four corners by 

 tlie so called parietal spines. The spines of the margin 

 of tlic preopercnlum are as a rule four in nund)er; 

 the operculum and interopei-cuJum are generally armed 



with sjiines at the hind upper corner, and the sub- 

 operculuin at the lower corner. As a rule, too, the 

 clavicular and supraclavicular bones are furnished with 

 spines at the top. The system of the lateral line is 

 generalh' well-developed in these fishes, both on the 

 head and on the body — in the former region it is 

 most developed in tlie Four-horned Cottus — and on 

 the body there are usually distinct lateral branches of 

 the lateral line proper, but apparently' the system is 

 here developed posteriorly only at an advanced age, 

 and often enough the hind portion of the lateral line 

 is pai'tlv incomplete or e\e\\ totally wanting on the 

 posterior half of the sides. 



Another distinctive point in the Cottidcc is the ex- 

 ternal dift'erence of sex, \vhicli is most often sharply 

 marked'. Besides the fact that the females are usually 

 more numerous and larger than the males, the latter, 

 at least when full-grown, generally have a genital pa- 

 pilla at the vent; more marked spinous warts on the 

 skin and more highly developed spines on the inside 

 of the.i-ays of the pectoral and ventral fins, the latter 

 of which ai'e most often elongated; higher dorsal fins; 

 and a dift'erent coloration, often spotted with white. 



The centre of the geographical distribution of the 

 CottidfC — if ^ve disregard their scaly representatives 

 in India, and Australia — lies in the Arctic and Boreal 

 seas: some species, too, ai'e circumpolar. They really 

 l)elong to water of moderate depth where the bottom 



" Of llie first ray in (he annl fin of HeiiiHepklohin trachnrus, from Kamlclialka Cuv., Vai,. {Hist. Nat. Poiss., vol. IV, p. 278) say 

 that it may possilily be a spinous ray ("pourrait rlre epineiix"), but in specimens from Behring Island it is distinctly articulated. 

 ' Cf. Coi,i,|.:tt, NorgeA Fiske, Vid. Selsk. Forh. Clirist. 1874, Till.-ogsh., p. '2y. 

 ' Cf. Li'TKKN, Vid. 5Iedd. Xafurli. For. Kbhvn 1876, p. 387. 



