TWENTY-FOUBTH ANNUAL MEETING. 



sory nerves. . . . Regarding the auditory organs, in the fishes only the internal 

 ear is present, without the additional drum cavity and external ear which we find in 

 the higher forms. In the sharks the auditory labyrinth is surrounded by cartilage, 

 but in most fishes it is free. . . . The higher vertebrates carry out the plan be- 

 gun in the sharks, the Ikbyrinth being completely protected by an osseous capsule." 

 Audition is assisted in some of the higher forms by the erection of a sort of sound- 

 ing-board from the integument — the external ear. This becomes a very expressive 

 feature in some forms, as in Equus. 



"The eye is rather more elaborated regarding its internal structure in the higher 

 vertebrates,"' and its position in the face is such as to make it a very important ad- 

 junct in expression. It is considered to convey as much expression as the facial 

 features, and becomes expressive at an earlier stage in the evolution of the face. 

 That is, animals which have little or no facial expression, whose features are unde- 

 veloped and immobile, have eyes which are very expressive, and indicate the feelings 

 and passions with no uncertain signs. Its supporting structures have little influence 

 in modifying the features, as they are not extensive in the class. 



The olfactory sense organ is more important, regarding the influence it has in 

 modifying the facial contour of animals. The structures erected for its accommo- 

 dation present great variety, and are often very extensive. The organ of smell "first 

 appears as an involution of the skin in the lowest forms, and in Amphioxus is rep- 

 resented by a ciliated sac near the anterior opening of the neural canal,"' and retains 

 this relative position in all vertebrates. "In fishes the forms of this organ are very 

 various, but in the sharks a groove leads to the roof of the mouth, which is after- 

 ward changed into a canal in other higher forms." From this beginning the organ 

 is developed in various forms, and in some animals, as the ruminants, an extremely 

 extensive structure is erected, with long and high nasal bones and large turbinated 

 bones, for its accommodation. 



How much the sense of taste has had to do with the development of the tongue, 

 and consequent effect upon the oral structures, we can form no estimate, for these 

 structures seem to be erected mainly for the accommodation of the dental armature. 

 The jaws vary as the food habits cause the teeth to vary, or as the teeth may be de- 

 veloped for other purposes. As these are modified to adapt them to the food hab- 

 its, the jaws are formed to support the teeth, as, for instance, in the carnivora or 

 the ruminants. The mouth is developed, from a mere orifice for the reception of 

 food for its introduction into the alimentary canal, to the position of an important 

 facial feature. In the higher forms the lips advance from mere prehensile organs to 

 becoming conspicuous features in facial expression, for in man the mouth is the 

 most expressive of the mobile features. 



Regarding the face in general, in the lowest vertebrates (Mr. Wright, o^j. cit.) — 

 the tunicates, acrania, etc., those headless vertebrates which are scarcely differen- 

 tiated from the moUusca and were long classed with them — there seems to be little or 

 no provision for the special senses, and, of course, no trace of a face. In the lam- 

 preys occurs the first indication of a skull, and two eyes are present, the proper 

 vertebrate number. The sharks have the eye and ear organized much like the higher 

 vertebrates. The mouth is placed back of the tip of the snout, and in this class the 

 lower jaw begins to assume the form of the higher vertebrates. Throughout the 

 class of fishes there is little to be learned as to the face. The skull is well developed,' 

 the eyes are large and expressionless, and the mouth is moved forward to the end of 

 the snout. In the eels the face has advanced a little, and is nearer the reptile form. 

 Many curious forms of fishes have remarkable, often grotesque, facial forms and 

 expressions — if such low faces can be said to have expression. Comparative physi- 



