Workman, Nej-vcs of the Cat Fish. 409 



narrow space between the r. ophthalmicus superficialis V dor- 

 sally and the optic nerve ventrally, then turns gradully outward 

 under the m. adductor arcus palatini, continuing to lie slightly 

 ventrally of the ophthalmicus superficialis V and dorsally of 

 the other orbital structures until it enters the superior oblique 

 muscle. 



///. The oculomotorms likewise immediately upon its exit 

 from the brain is crowded close up to the ganglionic complex, 

 following its innermost angle close below the fourth nerve until 

 the r. ophthalmicus V separates from the rest of the complex. 

 The oculomotorius now turns outward under the ramus last 

 mentioned closely followed by the abducens, emerging from the 

 cranial foramen dorsally of the latter and internal to the infra- 

 orbital trunk. It now runs out cephalad and laterally over the 

 infra-orbital trunk and dorsally and laterally of the VI nerve, 

 the two being bound up in the same sheath, and divides into 

 two unequal portions, the smaller one being dorsal. The smaller 

 branch runs out under the superior rectus muscle, which it 

 innervates, crossing over the other rectus muscles. 



A short distance cephalad the third nerve again divides, 

 the two branches, along with the sixth nerve, here being 

 crowded in between the infra-orbital trunk, lying ventrally, and 

 the m. rectus superior. F'urther cephalad the m. rectus exter- 

 nus slips in below them and the m. rectus inferior lies above 

 the more mesal branch, the lateral branch supplying this mus- 

 cle. The mesial branch runs cephalad under m. rectus internus, 

 where it divides, sending one branch directly dorsad to inner- 

 vate this muscle, the remainder continuing cephalad in the orig- 

 inal position to supply the obliquus inferior. 



Wright states ('84, p. 365) that in Ameiurus catus the 

 ventral branch of the oculomotorius runs over the rectus infe- 

 rior and rectus internus, while AUis ('97, p. 520) says that the 

 ventral branch runs ventrally of these muscles in Ameiurus. 

 Allis does not mention the species of Ameiurus which he dis- 

 sected, but presumably it was A. catus. Our examination of 

 A. melas confirms Allis' account, rather than Wright's. The 

 relations of the organs described in Ameiurus melas are illus- 

 trated by the accompanying diagram, which should be com 

 pared with the similar diagrams given by Allis ('97, Fig. 12) and 

 with the diagrams of Menidia and Amblystoma by Herrick 

 ('99, Figs. 13 and 14). It will be noticed that the arrangement 

 in Ameiurus corresponds to the ganoidean arrangement as 

 given by Allis, rather than to the teleostean arrangement as 



