386 CETACEA. 



tubes enveloping the larynx above, below, and on its sides, and however it may be 

 bisected, these tubes are always brought into view. No other glandular body is 

 visible in tliis larynx. 



The foregoing peculiar deeply honey-combed structure of the basal portion 

 of the inside of the larynx is apparently of rare occurrence among the Cetacea. 

 It must not be confounded with the mesial laryngeal sac described by Eschricht and 

 Reinhardt^ in the Greenland Right Whale {Balcena mysticetus), and by Knox^ in 

 Fhjsctlus, Carte and Macalister ^ in Balcenoptera rostrata, and by Murie* in Risso's 

 dolphin, Qrcmifus griseus. The two first mentioned of these anatomists do not 

 describe any peculiarity in the mn.cotis surface lining inside of the laryngeal sac, 

 neither do Carte and Macalister make mention of any glandular structure in connec- 

 tion mth it in the Pike Whale. Miirie, however, in his description of the larynx 

 of Risso's dolphin, states that at the lower end of the perpendicular epiglotto- 

 arytenoid passage the longitudinal folds were here and there interrupted by shallow 

 glandular ]Dits and depressions, and that among these occurred the orifice into the 

 laryngeal sac. These glandrdar pits and depressions alone seem to correspond to 

 the honeycombed glandular structure figured on Plate XXVIII, fig. 2. 



I made repeated microscopic examinations of the structure of the aforesaid 

 glandular cry2:>ts. One specimen of a vertical section under a low power is shown 

 in PL XXXVII, fig. 6. This exhibits a basework of trabecular fibro-elastic tissue, 

 within the mesh-work of which are here and there dispersed variously sized and 

 shaped spaces or closed follicular recesses (/!) surrounded by patches of a glandular 

 stroma (^.). At several points also the connective tissue has muscular packets (ot.) 

 running through it, and traces of capillary vessels (».) are met with. The free 

 surface of the membrane is of a velvety, villous or rather papillary nature, studded 

 with either elevated or depressed simple mucous glands {g.*). Unless it be to 

 aiford a mucous lubrication to the laryngeal surface, it is difiicult to assign any 

 distinct office to the extensive glandular area under consideration. 



Cartilages of the larynx (PL XXVIII, figs. 2, 8, and 9). — The cartilaginous 

 framework of the larynx is also found to differ from that of Tlatanista, in the less 

 develo]iment of some of its constituents, notably the cricoid cartilage ; whereas it 

 closely approximates to the form and structure of the same organ in Globicephalus. 



The cricoid cartilage is nearly a facsimile of that of the last named genus 

 and, hke it, has an imperfect ring (fig. 8) ; the two ends of the cartilage being 

 separated in tlie mesial line by a wide membranous interval. 



The thyroid cartilage resembles that of GloUcej^lialus B;n.di'hsL& no anteriorly pro- 

 jecting body as in the Susu, Platanista, and is not notched posteriorly. Like this 

 genus it has a short anterior cornu, behind which the posterior cornu is expanded 

 into a flat plate ; this contracts, however, to a narrow rod as it approaches its 

 cricoid attachment. 



1 Itecent Mem. Get. Eay Soo. Publ. 1866, p. 102. ^ pm_ Trans., vol. 158, 1868, p. 238. 



2 Cat. Prep. Whale, p. 11. -i Journ. Auat. and Phys., vol. v, 1871, p. 127. 



