COTTOMOKI'IIS. 



193 



MI5KAMII.V 



T R 1 (i L I X M. 



JJcdd <illi-(lssC(J. Ail-l/l(l(li/rr jircsviil. 



Tlic iD'csence of the ;iii'-l»l;i(I(lci- iiud IIk; ajjpeiiraiioe 

 of the head, wliicli is ahuost naked, hut anaed hy tlie 

 thickening" and granulation of the external bones, to- 

 gether with the fairly uniform rovering of scales on 

 the body, distingy^iisii the subfanuly of the Gurnards 

 from that of the true Cottoids. In the preceding sid)- 

 family, hoNvever, we have seen numbers of intermediate 

 forms l)etween it and the Gurnards. In a specimen of 

 Coitus clavif/er a great part of the head displays the 

 same nakedness and the same gi'anulation; but the most 

 striking external similarity appears in the spines which 

 occur along the base of the dorsal tins in Centrider- 

 )iuc]iflii/s Jhi Ilia fits, Coffiis Lilljelxm/ii' and the young spe- 

 cimens of ('. hubaJis. Similar spines are here a con- 

 stant character of that genus ^\dlich has given its name 

 to the subfamily, and here the}- are firmly attached to 

 the subjacent interspinal bones, a circumstance which, 

 as a rule, renders their number constant in each spe- 

 cies and equal to the total number of ravs in the two 

 dorsal tins. The difference between the upper and 

 louver rays of the pectoral fins, ^vhich is ^ve\\ marked 

 in the preceding subfamily, is here maintained in one 

 of two ^vays: either some of the lower rays become 

 free, digitate organs of touch and motion, or the upper 

 (smaller) part of these fins (in Dacfylopfenis) is wholly 

 detached from the lower (posterior). In connexion 

 with the cuirass of the head ^ve find a marked de- 

 velopment of the bones of the sul)orbital ring, -which 

 are firmly united posteriorly to the preoperculum and 

 anterioi'ly cover the sides of the whole snout, projecting 

 to a greater or less extent — in some forms like spa- 

 tulate processes — beyond the snout itself, and at the 

 same time covering the maxillarv l^ones, when the 

 tnouth is closed. The development of tlie air-bladder 

 constitutes a distinct difference from the preceding family: 



the sounds which flic (Jurnards are caiialjlc of producing 

 much more gcneralK and more loudly — -a cii'cumstance 

 which has given tliem their Swedish name, knorrhanar 

 ("Crooners") — arise from or at least are intensified by the 

 vibrations of the air-l)laddei'. These vibrations are due 

 to the strong contraction, accompanied also by rapid 

 \ibrations", of the muscular sheathing of the air-bladder 

 itself, of the adjacent infracostal muscles or even of 

 the large lateral and abdominal muscles. For the same 

 purpose the air-bladder is furnished with special nmscles, 

 and also, probably for the same pui'pose, the propertv 

 of changing the strength and tone of the sounds, gene- 

 rall}- divided into chambers by a constriction, either 

 anteriorly, as in Tii(/hi f/iouardus, ov anteriorly and 

 posteriorly, as in Dacftjloph'rus: it may also have lateral 

 processes, as in Trigla luccrna, in the form of long 

 horns, lying along the sides'. The gill-openings are 

 generally normal in these fishes; and tiiere is a pei-fect 

 branchial slit even behind the fourth branchial arch. 

 Through the strong covering of scales on the body 

 several of these fishes, notably Dactyloptenis and Peri- 

 stedion, come so near the following family (Af/onidce) 

 that they have sometimes" been referred to it; but the 

 strucfui'e of the head and the air-bladder speaks in 

 favour of their retention close to the Gurnards. 



The appearance of the Gurnards is peculiar, but 

 their manner of life still more so. The Gurnards and 

 Malarmats are realh" to be regarded as bottom-fishes 

 wdiich use the free, lower rays of tlie pectoral fins as 

 feelers in searching for food at the bottom, or even as 

 creeping-organs, and which often betray, by the traces 

 of wear in the points of the prominent preorbital bones, 

 tliat these bones have been used to root up the bottom. 

 But they are frequently found in the open sea, and 

 are then scarcely inferior in swiftness of motion to 



" According to DuFOSSli. LlXX«US, in bis concise, but telling, style, described this sound witli perfect fidelity to nature, and hinted 

 at its source in Triyla gurnarchis: ''Captus in abdoniine iimrniurat. moribiindus treiiiit" (Fauna ^uecica, ed. II. p. 120). Cf. also Mobeau, 

 Comptes Rendus, 1864, II, p. 436. 



* Cf. Yabrell, British Fishes, ed. 2, vol. 1, p. 40; Kkhyeh, Danmarks Fisle. vol. 1. p. IIG: Dufoss6, .\nn. d. Sc. Nat. ser. 5, 

 Tome XIX (1874). art. No. 5, pp. 38 etc., pi. Ui — 19: Tome XX (1874), art. No. .3. pp. 47 etc.; Sobensen, Om Lydorganer hos Fiske, 

 p. 129. 



■^ GC.NTHEi!. Iiitrod. .Stud. Fish., p. 481 (Handt'. Ichthijol.. p. 341). 



Scandinavian Fishes. ~"' 



