662 



SCANDINAVIAN FI>Slli;s. 



Tliis chnrnctcr is ncci)iii|i:iiiie(l, liii\\('\er, hy several 

 otliei' i)eculiai-ities, most of whirli call to iiiiiiil tlie Ilcioi- 

 I)raiiciis. Tlie l(o(h' is scaleiess, Imt in <4('iieral coinpicteh" 

 (■ov('i'c(l witii (Tanoid-likc plates, tlioiiriii these may 

 sometimes he thin and coated with skin, so that they 

 l)e<ome indistinct. rhe\' aiv arranired in longitudinal 

 and transverse rows. 'I'lii.' numlier ot the transverse 

 vows is usually equal to tliat of tlie vertebra-, to tlie 

 proeesses of which they are more or less closeh united; 

 .and in conse(|uenee tlie\' generally form distinct seg- 

 mental rings round tiie hod\'. In most of the Lopho- 

 branclis and especially in the I'ipetislies tlie body is 

 Inghly elongated, like that of tlie Eels or the Flute- 

 moutiis, and the snout is produced as in the lattt-r 

 forms. The branchial arches are incomplete, consisting 

 in each case of a single cartilaginous l)one: the epi- 

 branchial and u|)per pharyngeal bones, as well as the 

 iivpobranciiial bones, are wanting. The interchniclcs 

 are present, but are not externally \isil)le. 



The oi'gans of motion are feelile and the muscula- 

 ture as a whole is not much developed; but in the motory 

 muscles of the fins Rollett" has been enabled to observe 

 a fact tiiat seems calculated to possess tlie greatest ini- 

 jiortance for tlie ex])lanatiun of the structure and func- 

 tion of the striated muscles. Each of these muscles 

 consists, as is well known, of a number of small fibres, 

 corresponding to large cells, each with its envelo])e, a 

 thin membrane, and its contents. \Mthin the thin niem- 

 lirane, the sarcolemma^ that confines the muscular HIire, 

 we find two essentially distinct substances, the tii'st, 

 which has been named by KCiiXE rhabdia, the staff- 

 sidistance, divided into a number of cubical, parallelo- 

 pi])oid, vii'gulate, or lamella)' parts, ari'anged beside 

 each otiier in longitudinal or transverse rows, but in 

 general at very minute intervals, which are filled by 

 the second sultstance, the sarcopIdfuiKi, a kind of ]iro- 

 toplasm with nuclei distributed among it. Tlie great 

 muscles of the bod-c in the tin}- Sea-horse are also of 

 this structure; but Rollett has pointed out a remark- 

 able difference in the relative propm-tions (jf these two 

 substances in the muscles that set the fin-rays in vibra- 

 tion. Here, where the movements are too rapid for the 

 eye to follow lliem, the sarcoplasm pi'eponderates greatly 

 ovei' the rJiahdio. Up to the ])resent time science has 

 not fully succeeded in elucidating the significance and 



co-operation of llii' two sulistiinces in the contraction 

 of the muscles. But, as oiih' the sarcoplasm together 

 with the sarcolemma comes in immediate contact with 

 the end ajiparatus <if tin.' tibi-ilhe of the niotorx' nerves, 

 we may at least conjecture both that the physiological 

 significance of the two substances is different, and that 

 the operation cif the ner\'ous po\ver varies according to 

 the different (piantity and distribution of the two sub- 

 stances in a muscular tibre. Roli.ett's observation of 

 the Sea-liorse — together with several otlier observations, 

 e. g. of the wing-muscles in insects — entitle us at 

 le;ist to the assumption that extremeh' rapid muscular 

 motion may be promoted bv the nnn'e advanced deve- 

 lopment of the sarcoplasm. 



'i'lie Lopholiranchs are characterized, it is true, by 

 a considerable reduction of the true organs of motion; 

 but one genus, Soh'ii(}sfmiiiis from the Indian (_)cean and 

 Australia, tlii' type of a distinct family, is fully equi])- 

 ped in this res])ect, in |)articular with a high anterior 

 dorsal fin, a large caudal tin. and Ix.ith long and bi'oad 

 ventral fins. All the other genera, which together form 

 the faniih' S'i/iii/jiiiflii(he, are destitute both of the first 

 dorsal fin and of the venti-al fins: the anal, caudal, and 

 finalh' c\ en the ])ectoi'al fins are reduced in most of 

 them, and entirely disa])pear in some forms. When the 

 caudal fin has disappeared, the tail becomes a prehensile 

 oi'gan, more or less developed, which fishes of this 

 description, e. g. the well-known Sea-horses, curl round 

 the branches of seaweeds or round other suitable objects, 

 in <ii'(ler to hold tliem.sehes fast. 



All these fishes are feeble creatures, which depend 

 for their protection cliieflv on their resemblance to the 

 surrounding objects. (_)ur small Pipefishes closely re- 

 .seinble the thread-algtp (ulrcf) to whicdi they often 

 attach themselves, and several Sea-horses develop foliate 

 gr(.)wths sometimes of the most fantastic shapes, h\ 

 means of which tlie\- acipiire a deceptive likeness to 

 the seaweed. The\' must seek tlieir food among the 

 weakest minute animals, for their toothless mouth is 

 most like a sucking tube (cf. alK)ve, pp. 263 and 264, 

 on the internal folds of tlie mouth in the (Jollies). 



In the method of their reproduction all the Lopho- 

 branchs of vvhicli we lia\"e :n\\ information on this 

 head, sho\\- the peculiarity that they carry the impreg- 

 nated eggs and, until they can help themselves, the 



" Ueber die Flo-tfciniui/ilcein lies Seep/ei-ilclieiis {HipptnainpHs nntiqiioi-nm) viiil iilry Miifkcl.^tnictnr im Allijcmcineii, Arcli. Mikr. Ai)ot. 

 XXXII (1888), p. 2.33. 



