206 DE. J. MimiE ON THE OEGANIZATION OF THE CAAING WHALE. 



Fig. 27. The blow-hole of the White-beaked Bottlenose [Lagenorhynchus albirostris) 

 opened by retroverting the lips. It shows the alar protuberances, smooth- 

 surfaced posterior wall, and antero-lateral corrugated membrane, a, anterior, 

 and ]}, posterior lips ; sp, septum narium ; c, cartilaginous cushion, the arrow 

 being directed into the maxillary pouch ; r, cuticular ridges of the spiracular 

 cavity. 



Fig. 28. Diagram of the narial pouches and spout-hole of GloMceps. 



B, blow-hole ; spc, spiracular cavity ; p, premaxillary sac ; m, maxillary, and nf, naso- 

 frontal sacs. 



Fig. 29. Sketch of the right orbito-auricular region of the male L. albirostris, showing 

 a dissection of the ear-muscles &c. 



ac, auditory canal ; Bet, retrahens aurem ; Atr, attrahens ; Atl, attoUens ; Te, tem- 

 poralis ; fav X std, facial vessels, nerve, and Steno's duct. 



Fig. 30. An underview of portion of the left mandible and pterygo-maxillary region 

 of the same Lagenorhynchus. Dissected to show the vascular rete inter- 

 vening between the lower jaw and basis cranii, and its relation to the 

 pterygoid muscles &c. 



Mn, mandible ; z, zygomatic bar ; Ipt, internal pterygoideus ; Ept, external pterygoid, 

 severed ; Rete, of the basis cranii and mandible ; imx, internal maxillary artery ; 

 id, inferior dental artery ; a, artery, and v, vein, pterygo-maxillary branches ; pnm, 

 postnarial muscle. 



Fig. 31. Segment of the base of the skull of the Caaing Whale, which displays from 

 below the tympanic region, the Eustachian tube, its enlargement, and the 

 extensive rete mirabile covering its membranous walls and the adjoining 

 depressions. 



c, left condyle ; Boc, basioccipital ; Eoc, exoccipital ; ty, tympanic bulla ; ma, malar ; 

 z, zygoma ; pt, pterygoid ; P.na, posterior nares ; ac, auditory canal ; Eus, Eustachian 

 tube partially opened ; Bete, basicranial plexus ; vp, venous plexus ; of, condyloid 

 foramen ; fn, facial nerve ; she, stylohyal cartilage. 



PLATE XXXIII. 



Fig. 32. Portion of oesophagus, the compound stomach, and part of the duodenum of 

 the Pilot Whale. All more or less opened to show their internal walls and 

 connecting passages. Their relative positions are necessarily displaced, to 

 exhibit interior structure. 



05, oesophagus ; gl, oesophageal gland ; 7, /*, II, III, & IV, the four separate gastric 

 cavities or stomachs; nos. 1, 2, 3, 4, 5, 6, lie over the pointers which indicate the 

 several passages from the oesophagus to the commencement of the small intestine ; 



