— 78 — 



clature heretofore adopted in my works, excepting only as it relates to the lateralis nerves. In refer- 

 ring to these nerves I shall replace facialis by lateralis, and refer to the so-called dorsal and ventral 

 lateralis roots of the trigemino-facialis couiplex as the lateralis trigcmini and lateralis facialis res- 

 pectively. The brain is not described, as no special examination of it was made. 



NERVUS OLFACTORIUS. 



The nervus olfactorius arises in Scorpaena from the anterior end of a lobus olfactorius which, 

 as Stannius ('49) has said for Cottus and Trigla, lies beneath the anterior end of the cerebral hemisphere. 

 The nerve is long and relatively slender, and the two nerves run forward, close together, a certain 

 distance in the cranial cavity, there lying immediately dorsal or dorso-mesial to the nervi optici. 

 The two nerves then enter a small median recess in the membrane that closes the orbital opening 

 of the brain case. From this recess a membranous tube leads forward on either side of the posterior, 

 membranous portion of the interorbital septum, each tube conducting the corresponding nervus 

 olfactorius into the orbit. There the nerve continues forward along the lateral surface of the cartilag- 

 inous portion of the interorbital septum, passes dorsal to both of the oblique muscles, close to their 

 origins, and traversing the olfactory canal in the antorbital process reaches the nasal pit. 



In Menidia the olfactorius is said by Herrick ('99, p. 239) to be ,,crowded under the m. obliquus 

 superior near its origin", which if it means that the nerve passes ventral to the muscle, must be ex- 

 ceptional for fishes (Stannius, '49, p. 7). 



No indication of Locy's ('05) nervus terminalis could be found in any of the fishes of the group. 



NERVUS OPTICUS. 



The nervi optici are large and much pleated in all of the fishes of the group, as Stannius has 

 already stated for Cottus and Trigla. In Scorpaena, as well as in Cottus, Sebastes and Trigla (Stannius), 

 the chiasma is a simple crossing of the nerves, the left nerve lying dorsal to the right one in all the 

 specimens examined, excepting in one specimen of Scorpaena. In that one specimen the right nerve 

 was the dorsal one. 



Beyond the chiasma the nerve of either side, in Scorpaena, runs almost directly forward in 

 the cranial cavity until it reaches the anterior edge of the basisphenoid, where it turns antero-laterally, 

 pierces the membrane that closes the orbital opening of the brain case and, entering the orbit, courses 

 onward to the eyeball. 



NERVUS OCULOMOTORIUS. 



The nucleus of the nervus oculomotorius lies near the median line, mostly ventral to the fas- 

 ciculus longitudinalis dorsalis, but, as in Menidia, partly dorsal to it. The fibers from the dorsal 

 portion run downward mesial to the fasciculus and, joining the other fibers, turn ventro-laterally 

 and issue from the base of the brain dorsal to the hind end of the lobus inferior. From there the nerve 

 runs forward along the lateral surface of the dorsal portion of the lobus inferior, lying at first ventro- 

 mesial to the nervus trochlearis and then in similar relation to the profundus ganglion and truncus 

 ciliaris profundi. In one instance the nerve was, in part of its course, closely applied to the mesial 

 surface of the communis ganglion of the trigemino-facialis complex. While still in the cranial cavity 

 it separates into its superior and inferior divisions, both of which issue through the oculomotorius 

 foramen in the proötic, usually alone, but in one 55 mm specimen, and on one side of the adult 

 specimen used for figure No. 28 accompanied by the truncus ciliaris profundi. 



