Levator l;ibii superioris 



maxillre - ...... V. 



MUSCULAR SYSTEM 187 



Visceral Muscles. 



Fishes. The visceral muscles of Fishes l have been most 

 satisfactorily investigated in Elasmobranchs ; and are classified by 

 Fiirbringer us follows : 



A. Cranial or cerebral muscles (consisting originally of trans- 

 verse or circular fibres) supplied by the V th , VII th , IX th , 

 and X th cerebral nerves. 



1 . Constrictor arcuum visceralium,mc/. constrictor superficialis 

 dorsalis et ventralis. 



Inner vat ion. 

 ioris } 



,, |- 



, , ] >alpetme nietitantis 2 J 

 ,, rostri ^ 



,, hyoiiiandibularis VII 



Depressor rostri f 



,, maiidibularis et hyomaiulibularis J 

 Interbranchiales .......... IX, X. 



Trapezius ............ X. 



2. Arcuales dorsales ........... IX, X. 



3. Adductores, incl. adductor mandibuhv ... V. 



and abductores arcuum branchialium . . IX, X. 



B. Spinal muscles, originally longitud- ) s . . . , 8 , 



inal, and divided, like the other 

 trunk-muscles, into myomeres. 



(a) Epibranchial spinal muscles, dorsal to visceral skeleton. 



4. Subspinalis ....... Spino-occipital nerves. 



( Spino - occipital nerves, 



5. Interbasales ....... -< as well as the first 



( spinal nerve. 

 (6) Hypobranchial spinal muscles, ventral to visceral skeleton. 



6. Coraco -arcuales, incl. coraco- Spinal nerves.and partly 



branchiales, coraco - hyoideu * C f K , 



I--, i - J } of the spino- occipital 



and coraco-mandibularis . . I 



\ nerves. 



In the Ganoidei, Dipnoi, Teleostei, Amphibia, and Amniota 

 there are no epibranchial spinal muscles, and the hypobranchial 

 muscles have a very different form from those of Elasmobranchs : 

 in Teleosts, for instance, they are much simplified. In Amphibians, 

 as already mentioned, the rectus system of the trunk is only 



1 In Cyclostomes there is a remarkable transformation of the cranio-visceral 

 musculature in correspondence with their peculiar cranial skeleton (suctorial 

 apparatus) and branchial basket. It is covered over secondarily by the trunk 

 muscles. 



2 This muscle lias nothing to do with the other eye-muscles. 



3 These are spinal nerves emerging from the occipital region of the skull (cf. 

 under Xervous System), 



