74 EDWARD PHELPS ALLIS, JR. 



apparently passing ventral to the nervus trochlearis and joining 

 the first three small branches of the nerve. The relations of this 

 profundus nerve to the oculomotorius thus differ radically from 

 those in Polypterus, but it seems probable that its first three 

 branches correspond to the frontal branch of the nerve of the 

 latter fish, and the two larger ones to the nasal branch. A small 

 nerve is said to arise from that part of the trigeminus ganglion 

 from which the ophthalmicus profundus has its origin, and to 

 immediately join the ophthalmicus superficialis facialis, and 

 Pinkus doubtfully calls it the ramus ophthalmicus superficialis 

 trigemini. Comparison with Polypterus would, however, indi- 

 cate that it is a persisting remnant of the communis component 

 only of the ramus ophthalmicus superficialis of the latter fish. 



In Ceratodus there is a bar of cartilage that represents the 

 pedicel of the alisphenoid (Allis, '14), and the ophthalmicus pro- 

 fundus of Greil's ('13) descriptions of embryos of this fish issues 

 from the cranium anterior to that bar. The nerve is then shoAMi, 

 in one of Greil's figures (I.e., fig. 8, pi. 55), separating into two 

 branches, one of which is evidently a portio ophthalmici profundi 

 and the other a typical so-called ophthalmicus profundus tri- 

 gemini. The ophthalmicus superficialis of this figure, called by 

 Greil the ophthalmicus superficialis trigemini in another figure 

 (fig. 4) on the same plate, receives no branch from what is ap- 

 parently the general cutaneous ganglion of the trigeminus, the 

 profundus thus supplying, as in Polypterus, all the general cu- 

 taneous fibers sent to the dorsal surface of the anterior portion 

 of the head. 



In Amia I have fully described the nerves here concerned, 

 without, however, definitely determining their components (Allis, 

 '97). It is, however, probable that the ophthalmicus superficialis 

 contains lateralis, communis and general cutaneous fibers, and 

 it receives an important portio ophthalmici profundi from an 

 independent profundus ganglion, the root of the latter ganglion 

 issuing frcm the cranium anterior to the pedicel of the alisphenoid. 

 A delicate nerve that arises from the anterior end of the profun- 

 dus ganglion was considered by me to be a greatly degenerated 

 ramus ophthalmicus profundus. 



