CETACKA. 



the tympanum, which, in the Porpoise, is 

 only by contact, but in others by a bony 

 union ; the other attachment is formed by the 

 tendon, above described, being united to the 

 inner surface of the membrana tympani. Its 

 base articulates with the incus. 



" The incus is attached by a small process to 

 the tympanum, and is suspended between the 

 malleus and stapes. The process by which it 

 articulates with the stapes is bent towards that 

 bone. 



" The stapes stands on the vestibulum, by a 

 broad oval base. In many of this tribe, the 

 opening from side to side of the stapes is so 

 small as hardly to give the idea of a stirrup. 



" The muscles which move these bones are 

 two in number, and tolerably strong. One 

 arises from that projecting part of the tym- 

 panum which goes to form the Eustachian 

 tube, and running backwards is inserted into a 

 small depression on the anterior part of the 

 malleus. The use of this muscle seems to be 

 to tighten the membrana tympani ; but in those 

 which have the malleus anchylosed with the 

 tympanum, we can hardly conjecture its use. 

 The other (o) has its origin from the inner surface 

 of the tympanum, and passing backwards is 

 inserted into the stapes by a tendon, in which 

 I found a bone in the large Bottle-nose. This 

 muscle gives the stapes a lateral motion. What 

 particular use in hearing may be produced by 

 the action of these muscles I will not pretend 

 to say ; but we must suppose whatever motion 

 is given to the bones must terminate in the 

 movement of the stapes. 



" The immediate organ of hearing is contained 

 in a round bony process, and consists of the 

 cochlea and semicircular canals, which some- 

 what resemble the quadruped ; but besides the 

 two spiral turns of the cochlea, there is a third, 

 which makes a ridge within that continued 

 from the foramen rotundum and follows the 

 turns of the canal. 



" The cochlea (/c, Jig. 276) is much larger 

 when compared with the semicircular canals, 

 than in the human species and quadruped.'' 



Besides its greater relative size, the coch- 

 lea of the Delphinidte differs from that of 

 the human subject in the greater pro- 

 portional extent, and especially the form and 

 disposition of the scala vestibuli, which, in- 

 stead of being one compartment of a single 

 tube divided in the direction of its axis, is a 

 complete conical tube. It also forms an oblique 

 sigmoid curve before commencing its spiral 

 turns, which are two and a half in number. 



The semicircular canals have the same dis- 

 position as in Mammalia, but are relatively 

 smaller. 



Cuvier, in correcting the error into which 

 Camper had fallen when he denied the 

 existence of the semicircular canals in the 

 Whale, appears to have overlooked the fact 

 that they had previously been discovered in 

 the Cetacea by Hunter. And it is simply be- 

 cause they do not posses: any difference of 

 note as compared with other Mammalia, (ex- 

 cept in their relative volume to other parts of 

 the labyrinth which Hunter is careful to point 



out,) that they are not described by him with 

 the same minuteness and detail as the cochlea 

 and other parts of the organ. It may also be 

 observed that the more extensive researches of 

 Hunter preserved him from the error into which 

 Cuvier has fallen of ascribing to the Cetacea a 

 structure of the cochlea which is peculiar to a 

 small part only of the order. The depression 

 of the gyrations of the cochlea to nearly the 

 same plane, and their limitation to one and a 

 half in number, is certainly not applicable to 

 the Delphinidee, and it may be doubted how 

 far it can be with accuracy asserted of the 



The canals which establish a communication 

 between the labyrinth and the interior of the 

 cranium, viz. the aqueductus vestibuli and 

 aqueductus cochleae, are very large in the Del- 

 phlntdfE, especially the latter.] 



Tuste. This sense probably exists in the 

 Herbivorous Cetaceans, whose tongue, although 

 but slightly moveable, has notwithstanding a 

 complicated and delicate structure. But has 

 this sense a special organ in the Spouting Ce- 

 taceans ? Some doubts may be allowed to 

 exist on this subject. The tongue of the Dol- 

 phin and that of the Porpoise have neither 

 fossulate papillae nor conical papillee ; they only 

 present on their surface slight elevations, of 

 which the middle appears to be perforated, and 

 their edges are fringed, as if for multiplying 

 the sensations of touch. 



Touch. The general organ of touch, the 

 skin, has formed, in the Spouting Cetaceans, 

 the subject of important researches, which have 

 given a more extended knowledge of this organ 

 in general than was before possessed. 



According to the observations of MM. 

 Breschet and Roussel de Vauzeme, there may 

 be distinguished in the skin of the Cetaceans, 

 as in that of other Mammals, six principal 

 constituents which either penetrate or are 

 superimposed on one another, but which are 

 severally destined to fulfil a special function. 



1. The derm or curium (le. derme), a dense 

 fibrous cellular texture, which contains and 

 protects all the other parts of the skin. In 

 the Whale it is constantly white and opake, 

 and its peripheral surface presents a series of 

 papillae, the intervals of which are occupied 

 by the epidermis, which forms for each a 

 sheath. 



2. The papillary bodies (les corps papil- 

 laires) consist of papillae covered by the derm. 

 They have a nacrous lustre, and are several 

 lines in length in the Whale, but are much 

 shorter in the common Dolphin and Porpesse. 

 These papillae are composed of fibres pene- 

 trated by vessels ; they originate from the sub- 

 cutaneous nervous plexus and return back again 

 to the same ; the derm serves merely as a 

 sheath to the papillae, the extremities of which 

 exercise the sense of touch. 



3. The sudorific apparatus (Vuppurcil sudo- 

 rifique) consists of soft, elastic, spiral canals, 

 which extend through the entire thickness of 



* See OSSCMI. Foss. vol. v. pt. i. p. 300, and 

 Lemons d'Anut. Compuivo, vol. ii. p. 4<S7. 



