FISHES. 321 



articular fissure, which the posterior frontal, and the mastoidean, 

 present to the frontal. 



The fasciculus is divided into two orders of ribbands, four external 

 and two or three internal. 



The four external (Nos. 30, 30) are inserted into the back of the 

 superior pieces of the four arches of the branchiae ; the internal into 

 the two first pharyngeans. 



These muscles raise the superior part of the apparatus, and draw it 

 towards the cranium ; at the same time, the external carry the arches 

 forwards, and dilate the intervals of the branchiae. 



A second fasciculus is attached to the cranium, behind the depressor 

 muscle of the operculum, and is connected to the extremity of the 

 mastoidean bone. 



It is composed of two ribbands, an anterior one (No. 32) which 

 goes to the superior piece of the fourth arch, more outwards than the 

 last of the externals of the preceding fasciculus, and a posterior one 

 (No. 33) which terminates in the tissue of the pharynx, behind the 

 third superior pharyngean. 



The functions of this second group are nearly the same as those 

 of the first. 



A third fasciculus consists of one muscle only, which is consider- 

 able (No. 41, pi. vi. fig iv.) and which commences at the internal and 

 posterior border of the third superior pharvngean, and passing across 

 the fibres of the pharynx, proceeds obliquely to attach itself to the 

 spine. 



This muscle, carries the entire apparatus backwards, raising it at 

 the same time as the two preceeding fasciculi. 



The superior part of the second arch has a particular muscle 

 attached to the side of the base of the cranium, nearly on the junction 

 of the great wing with the Basilar, and which passing horizontally is 

 inserted into the arch before the insertion of the external fasciculus 

 which this arch receives from the first fasciculus. 



The action of this muscle is to draw the two rows of arches nearer 

 to each other, and to the axis of the base of the cranium, in which 

 they are seconded by the transverse muscles proper to the apparatus, 

 which we shall describe by and bye. 



Three muscles act on the apparatus by means of the inferior pha- 

 ryngean in which they are inserted. 



One of them (No. 35) comes from the superior crest of the body of 

 the os hyoides, above the insertion of the great lateral muscular. It 

 proceeds to the pharyngean ascending obliquely behind ; and draw- 

 ing it downwards and forwards, acts as an antagonist to that which is 

 attached to the spine. 



The two others (Nos. 36, 37) go off from the humeral bone, 

 No. 36 from its inferior part, and ascending upwards; No. 37 from 

 its middle part, and it goes almost horizontally ; No. 36 lowers the 

 apparatus by drawing it backwards; No. 37 simply draws it back. 



The pericardium, and the heart, arc placed between these three 

 muscles, and their fellows on the opposite side. 



The muscles proper to the apparatus, are the transverse and the 

 oblique. The latter amount on the inferior surface to the number 

 vol. ii. y 



