THE MYOLOGY OF AMIURUS CATUS. - 325 



from their original position. According to this view the fibres of 

 the first muscle originally ran from the ceratohyal to ceratobr. i. , as 

 indeed slips do in Esox and the Cyprinoids ; those of the second from 

 ceratobr. i. to ceratobr. ii. ; and those of the third from ceratobr. ii. 

 to ceratobr. iii. This supposition is supported by the fact that in 

 other Teleostei there is a fourth obliquus ventralis and no slip be- 

 tween ceratobrs. iii. and iv., as in Amiurus. 



3. Musculi Transversi Ventrales, (No. 40, Cuv. ; includes 



Transv. j)haryngei, Vetter. ) 



These are two in number, exposed by the dissection required for 

 the preceding muscles. The anterior one, (Fig. 4, TV 1 ), extends 

 between the ceratobr. of either side of the fourth arch, across the 

 lower surface of the branchial apparatus, the posterior (TV 2 ) holds a 

 similar course between the inferior pharyngeals (ceratobr. v.) 



Action. — They approximate the arches of opposite sides, the an- 

 terior one also drawing them slightly downwards. 



The placing of the posterior muscle in a different category from the 

 anterior, under the name of pharyngeus tra7isversus, is'quite unneces- 

 sary, the two being serially homologous. The origin of these muscles 

 is indicated by the representative of the anterior one in the Cypri- 

 noids, it being there small and merely part of one of the obliqui 

 ventrales. 



4. Pharyngo-Clavicularis Externus, (No. 36, Cuv. ; Branchi- 



retractor, Ow.) (Fig. 4, PhE.) 



This muscle and the following one may be seen by the dissection 

 required for the hyobranchialis, et seq., or still better, by dividing a 

 specimen longitudinally exactly in the middle line. The hyopec- 

 toralis will have to be removed from its attachment to the clavicle 

 to expose the origin. The pharyngo-clavicularis ext. arises from 

 the upper surface of the clavicle behind the insertion of the hyopec- 

 toralis, and passes upwards, forwards and inwards, to be inserted 

 into the anterior extremity of the inferior pharyngeal (ceratobr. v. ) 



Innervation. — Branch from the fii-st spinal nerve. 



Action. — Draws the pharyngeal backwards, downwards and slightly 

 outwards, opposing the transversus and hyobranchialis. 



