▼OL. LXXVII.] PHILOSOPHICAL TRANSACTIONS. 335 



out any immediate action of muscles. The diaphragm in these animals appears to 

 be the principal agent in inspiration ; and the cavity of the thorax not being entirely 

 surrounded by bony parts, is of course less easily expanded, and the apparatus 

 for its expansion in all directions, as in the quadruped, does not exist here. 



The blow-holey or passage for the air. — As the nose in every animal that 

 breathes air is a common passage for the air, and is also the organ of smelling; 

 I shall describe it in this tribe as instrumental to both these purposes. There is a 

 variety in some species of this animal which is, I believe, peculiar to this order; 

 that is, the want of the sense of smelling; none of those which I have yet 

 examined having that sense, except the 1 kinds of whalebone whale: such of 

 course have neither the olfactory nerves, nor the organ ; therefore in them the 

 nostrils are intended merely for respiration; but others have the organ placed in 

 this passage as in other animals. 



The membranous portion of the posterior nostrils is one canal ; but when in 

 the bony part, in most of them, it is divided into 2 ; the spermaceti whale how- 

 ever is an^ exception. In those which have it divided, it is in some continued 

 double through the anterior soft parts, opening by 2 orifices, as in the piked 

 whale; but in others it unites again in the membranous part, making externally 

 only one orifice, as in the porpoise, grampus, and bottle-nose. At its beginning 

 in the fauces, it is a roundish hole, surrounded by a strong sphincter muscle, 

 for grasping the epiglottis; beyond this, the canal becomes larger, and opens 

 into the 2 passages into the bones of the head. This part is very glandular, 

 being full of follicles, whose ducts ramify in the surrounding substance, which 

 appears fatty and muscular like the root of the tongue, and these ramifications 

 communicate with each other, and contain a viscid slime. In the spermaceti 

 whale, which has a single canal, it is thrown a little to the left side. After these 

 canals emerge from the bones near the external opening, they become irregular 

 and have several sulci passing out laterally, of irregular forms, with correspond- 

 ing eminences. The structure of these eminences is muscular and fatty, but 

 less muscular than the tongue of a quadruped. 



In the porpoise there are 2 sulci on each side; 2 large and 2 small, with cor- 

 responding eminences of different shapes, the large ones being thrown into 

 folds. The spermaceti whale has the least of this structure; the external open- 

 ing in it comes farther forwards toward the anterior part of the head, and is con- 

 sequently longer than in others of thlo order. Near to its opening externally 

 it forms a large sulcus, and on each side of this canal is a cartilage, which 

 runs nearly its whole length. In all that I have examined, this canal, forwards 

 from the bones, is entirely lined with a thick cuticle of a dark colour. 



In those which have only 1 external opening, it is transverse, as in the porpoise, 

 grampus, bottle-nose, and spermaceti whale, &c.; where double, they are lon- 

 gitudinal as in the piked whale, and the large whalebone whale. These open- 



