DR. J. AfTJltTE ON THE WIIITE-BEAKED BOTTLENOSE. 153 



These two muscles are relatively weak lateral flexors of the 

 spine. 



DESCRIPTION OF PLATE V. 



Fig. 1. Hinder segment of the head of the White-beaked Bottlenose (Lageno- 

 rhynchus albirostris), dissected to show the first or superficial fleshy 

 layer, &c, connected with the blow-hole on the left side. 



2. The same specimen, displaying the second layer. 



3. The deeper third layer, maxillary sac, &c. 



4. Fourth layer, from above downwards, in the same animal, 



5. Undermost or fifth layer, naso-frontal sac, &c. 



The lettering in these five figures agrees, and is as follows : — 

 B, through the arrow, points to the blow-hole ; m, maxillary sac ; nf, naso-frontal 

 sac ; bl, blubber and superincumbent tissues ; of, occipito-frontalis ; Lis an, 

 levator labii superioris alceque nasi ; L sp, levator superioris proprius ; Z, zygo- 

 matici ; Py, pyramidalis, compressor nasi, &c. ; D an, depressor ali nasi, &c. ; 

 Nl, premaxillary muscle including naso-labialis, &c ; Sp, splenii ; Te, tem- 

 poralis. 



Fig. 6. A view of the articulation of the lower jaw, the joint being partially 

 opened. 



c, condyle ; e I, external lateral ligament; sq, squamous ; j, jugal ; 

 and /, frontal bones. 



7. The opened mouth, looked into from in front. The jaws are dragged 



asunder much more than is natural even at full gape, so as to bring 

 the faucial structures into view. T, tongue. 



8. The under surface of the right moiety of the tongue and parts between 



it and the pharynx. 

 Mh, mylo-hyoid ; G h, genio-hyoid ; and G kg, genio-hyoglossus 

 muscle ; T, tip of tongue in outline. 



9. Rough sketch of portion of the back of the palate and root of the tongue 



partially dissected. 



L, upright laryngeal funnel; Pg, palato-glossus ; Lp, levator pa- 

 lati ; T, tongue. 



LINN, JOUltN. — ZOOLOGY, TOL. XI. 



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