1806.] 



Proceedings of Learned Societies. 



51 



Thefe experiments were repeated on 

 the roach, the gudgeon, and the minnow, 

 with iimilar relblts. 



The mulcles of fifhes differ materially 

 in their texture from thole of other aiii- 

 hials. They are apparently more homo- 

 geneous, tijeir fibres are not lu much 

 t'afciculated, but run more parallel to 

 eacli other, and ai-e always comparatively 

 Ihorter. With regard to the mechanical 

 arrangement and phyliology of the late- 

 ral mulcles of the body of fiilies, lUr. 

 Carlille obfei-ves, that what ha\e been 

 denominated couches mufculuires, ov muf- 

 clcs luteruU, he a\ ill caUjerks : thefe le- 

 ries are compofed of thin maffes of mui- 

 cle, or, as they are commonly called, 

 Jliikes, wliich are tliicker upon the out- 

 ward edges, and become wedge-lhaped 

 towards tiieu' interior attacliments. Each 

 feries is feparated from the next adjoin- 

 ing by a membraneous partition, which 

 is moll apparent between the vertebral 

 and abdominal feries. 



After conlidering the feveral feries, as 

 the dorfal, vertebral, abdominal, and ven- 

 tral, Mr. C. oblerves, that the coats of 

 the blood-veflcls are of a delicace tex- 

 ture, and ealily ruptured. In order, 

 therefore, to lecure them from beir^g m- 

 jured by the violent and fudden actions 

 of the mufcles, the principal trunks both 

 of the arteries and \eins are inclofed in 

 oiTcous canals, formed by the bafes ofthe 

 fuperior and inferior fpinous proceifes, 

 and that their firft ramifications lie witiiin 

 grooves in the fpines. As they pafs out 

 to fupply the mulcles, their branches are 

 immediately fubdivided ; f j that a conii- 

 dcrabie velfcl foon becomes extremely 

 miiiule. 



The next obfcrvation relates to the ve- 

 locity of fillies, which, being but little 

 leis than that of the flight ofthe Avifteft 

 birds, is very remarkable, conlidering the 

 denlity of the medium in which tirey 

 fwiin. And although the large propor- 

 tion of mufcles, and their advantageous 

 application, may partly account for the 

 phenomenon, yet the powder would be in- 

 adequate to the effect, if it were nyt fud- 

 denly enforced, as is evident from the 

 flow progreis of eels, and fuch filhes as 

 are incapable, from their length and 

 tiixibility, of giving a fudden lateral 

 liroke. 



The qulcknefs and force of the aftion 



in the mufcles of fiflies are counterpoifed 

 by tiiC liiort duration of their powers. 

 Thofe accullomedto the diverlion of an- 

 gling are aware iiow fpeedily the Itrength 

 of a iiih is exhaufted ; tor if, when hook- 

 ed, it be kept in conllaiit action, it foon 

 lofes e^en the ability to preferve its ba- 

 lance, and turns upon its fide, fatigued 

 and inca|)ablo of motion. This has been 

 attributed to drowning, in conferjucnce 

 ofthe mouth being doled upon the hook ; 

 but the fame etlects take place w hen the 

 hook is fafteiied to the lide o ■ tail. Tliis 

 proflration of flrength may depend partly 

 on fear, and partly on interrupted refpi- 

 ration. The Ihortnefs of the mut'cular 

 fibres, and the multiplied ramifications of 

 the blood-veflfcls, are prooably peculiar 

 adaptations for the purpofe of gaining 

 velocity of action, which fecms to be in- 

 variably connetted with a very limited 

 duration of it. Such exam})les fjrm an 

 obvious contrail with the mufcular flruc- 

 ture of flow-moving auimal^, and with 

 thofe partial arrangements wliere unufual 

 continuance of attion is concomitant. 



Mr. C. mentions an inftance ofthe cy- 

 lindrical arteries lupplying il .w-moviiiJ 

 mufcles, which are capable '>f loa^-cou- 

 tiinied action. It is in the m jfcles which 

 aft upon the feet and toes of many birds, 

 and fecms to be an adaptation fi)r the 

 long exertion of thefe mufcles while tiiey 

 lleep, and alfo wlieii tliey alternately re>- 

 trutt one foot under the fe;aiiei-s to pre- 

 fei-vc it from the ettecis of cold. 



The mufcles of the human body which 

 perform the moft fudden actions have 

 their maffes of fibres fubdivided bv tranl- 

 verfe tendons, or arc arranged in a pen- 

 mforra direction. The femi-teudmofus 

 and femi-incmbranorus of the tingh ara 

 thus conftructed ; tlie former having its 

 ftelhy belly dividerL hy a narrow fafcia, 

 and the fibres ofthe latter being rauLred 

 in a haif-penniform manner. The re&i 

 abdominis are alio divided into iliort 

 maiios. by tranfveife tendons; and all 

 thefe mufcles are conjointly employed in 

 the action of leaping. 



Perhaps thefe obfervations may indi- 

 cate_the rcafjn for that diveriity in the 

 length of various mufcles which act toge- 

 ther : thus the organs of velocity are 

 joined with tiiofe oif power, and mutually 

 co-operate to produce a iimultaneous et- 

 feit. 



NEW 



