MusTELDS lj:vis. 223 



taste buds found in the roof of the moutli of certain fishes. 

 If these taste buds are modified lateral sense organs, the 

 nerves supplying them are likely to be made up of supra- 

 branchial fibres." Ewart further says (p. 45) of this so-called 

 trigeminal ophthalmic nerve in elasmobranchs in general, 

 " In sharks and rays this nerve svipplies the eyelids and the 

 skin over the anterior part of the cranium, but it also sends 

 fibres to the snout. More or less distinct in sharks, the super- 

 ficial of the ophthalmic of the trigeminal in rays consists of a 

 very few fibres which, on leaviug the trigeminal, at once more 

 or less completely unite with the superficial ophthalmic of the 

 facial." Ewart^s statement that branches of this trigeminal 

 nerve may innervate taste buds in the roof of the mouth is 

 clearly an error, and the nerve is, in all probability, the 

 homologue of the general sensory component of the ophthal- 

 mic nerve of Mustelus; that is, according to my conclusions, 

 the homologue of the portio profundi of the ophthalmicus 

 superficialis of Amia, and not of the portio trigemiui of that 

 fish. In Lsemargus there is, however, a branch of the oph- 

 thalmicus profundus called branch I by Ewart (17), which 

 also has the course of an ophthalmicus superficialis, the portio 

 profundi of the superficial ophthalmic nerve of this fish thus 

 apparently being represented by two separate branches. 



In Acanthias Hoffmann says (35, p. 287) that the portio 

 minor s. trigemini of the ramus ophthalmicus su})erficialis 

 is a branch of the rannis ophthalmicus profundus, and that 

 it is connected with the nervus trochlearis by a connnunicatiug 

 branch. He further says (p. 294), as I understand him, that, 

 after a certain stage of develojiment, that " Stiick dcs Troch- 

 learis, welches den Yerbinduiigsfaden niit deui Ophthalmicus 

 profundus bildet," becomes the portio minor of the oplithalmic 

 nerve. On page 287 he says that the nervus profundus arises 

 as an independent nerve, wholly separate and distinct from 

 a single, large anlage from Avhich the nervus trochlearis, 

 portio minor s. trigemini, ramus maxillo-mandibularis, and 

 communicating branch from the trochlearis to the trigemini 

 all arise. In a later work (36, p. 357) he says that " der 



