1901.] ANATOMY OJ? COOIA BKEVICEPS. 133 



corner of the blowhole. E, the valve, which is continued down the 

 left narial canal, f, vertical wall of the hind-lip of blowhole ; g, the 

 recess in this, h, left narial canal ; h', probe passed into it. i, probe 

 passed into the right narial canal, mm, median line of head, a, c, as 

 in fig. 2. 

 Fig. 4. The right-hand corner of the foregoing figure, enlarged, showing the 

 right narial canal and its lips. Letters as in fig. ?>. 



5. The naso-palatine canal exposed by slitting open the soft palate, seen 

 from behind, h, the lower end of left narial canal. _;', the lower end 

 of right narial canal. E, valve. fo/?.,basisphenoid bone, pteri/., ptery- 

 goid, prs., presphenoid. 



6. Dissection of the head, exposing (A) the upper spiracular chamber, 

 the front wall of which is laid open (nat. size), b, the narial canal passing 

 to the lower spiracular chamber, fib., fibro-muscular dermis. 

 i, probe passes through the left nostril into the spiracular chamber. 

 m, another probe passed into the nostril and issuing through the cut 

 end of a branched canal similar to n. mas., cut muscle. 



Plate IX. 



Fig. 7. Further dissection exposing lower spiracular chamber, the front wall 

 of which is turned downwards (\ nat. size). A, posterior, inferior 

 face of the upper chamber. B, the opened lower chamber ; r, its 

 posterior wall ; S, its anterior wall, mus., muscles. Jib:, fibrous 

 dermis. j, right narial canal disappearing behind the surrounding 

 tissue, b', the lower end of a probe passed through the inter-cavity 

 canal (h) of the previous figure. 6" and b'", another probe passed 

 through the dissevered part of this same canal ; b'", its entrance into 

 the lower chamber, c, probe passed down into the naso-palatine 

 canal. 



8. A group of papillae from the wall of the lower chamber ( X 4). 



9. Diagram of the nasal passages in the form of a projection seen from 



in front, a, blowhole, b, intercavitary portion of right narial canal. 

 c, lower end of right narial canal. E, longitudinal valve in the left 

 narial canal, h, left nai-ial canal, j, upper end of right narial canal. 

 n, branching outgrowths of this right narial canal, q, nasopalatine 

 canal. A, upper spiracular chamber. B, lower spiracular chamber, 

 the dotted outline indicates its dorsal extension behind A. m.e.s., me- 

 dian line of the head. 



Figs. 10-14 refer to the Alimentary Canal. 



Fig. IU. View of the dorsal surface of the paunch and stomach {\ nat. size). 

 a, oesophagus, b, paunch, c, cardiac chamber, d, commencement of 

 pyloric chamber which had been cut short. 

 11. Surface view of the lining of the oesophagus (slightly enlarged!, a, 

 section tlirough the same. 



Plate X. 



Fig. 12. Epithelial lining of the paunch (slightly enlarged). 



13. Mucous membrane of the cardiac chamber (slightly enlarged). 



14. A pari of the wall of the cardiac chamber has been removed, and the 



oardiao oriflee thus exposed (^ nat. size), a, oesophagus, b, paunch. 

 c, oardiao ohamber. a, the two ridges bounding the furrow leading 

 iVoui oesophagus to paunch, /.', probe passing from oesophagus. 

 f t probe pas«ed along the furrow into the paunoh. a, circular ridge 

 of mucosa and lubmuoora surrounding the orifice, h, k, free fold of 

 oesophageal mucosa projecting through thsorifloe. 



