548 
MR. SIBSON ON THE MECHANISM OF RESPIRATION. 
PLATE XXIV. 
Figs. III. a.b.c. Muscles of respiration in the Fowl (§§ 17-27). 
PLATE XXV. 
Fig. IV. Muscles of respiration in the Hawk (§§ 17-27). 
Fig. V. Muscles of respiration in the Stormy Petrel. 
Fig. VI. a. Muscles of respiration and ribs of the Swan, as they are on expiration. 
The sternum is pushed as near as possible to the spine. 
Fig. VI. b. Muscles of respiration and ribs of the Swan, as they are on inspiration. 
The sternum is drawn as far as possible from the spine. 
These views demonstrate the external intercostals to be inspiratory ; they 
are shortened in fig. VI. b., and the internal intercostals to be expira- 
tory. They are shortened in fig. VI. a. (§§ 22.25.26). 
PLATE XXVI. 
Fig. VII. (fig. Wl. b.c.d. Archives of the Royal Society). Muscles of respiration in 
the Porpoise (§§ 70-77)- 
Fig. VIII. (fig. XII. b . Archives of the Royal Society). Muscles of respiration in the 
Seal (§§ 55, & c. 62.67-69). 
PLATE XXVII. 
Fig. IX. (fig IX. b.c.d. Archives of the Royal Society). Muscles of respiration in 
the Calf (§§ 36, &c. 43). 
Fig. X. (fig. XL b.c.d. Archives of the Royal Society). Muscles of respiration in 
the Dog (§§ 55-69). 
PLATE XXVIII. 
Fig. XI. (fig. XII. b. Archives of the Royal Society). Muscles of respiration in the 
Rabbit (§§ 55, &c. 66.67). 
Fig. XII. (fig. XIII. b. Archives of the Royal Society). Muscles of respiration in 
the Otter (§§ 55, &c. 67-68). 
(Fig. X. a.b. c.d.e. Archives of the Royal Society). Muscles of respiration in the Ass 
(^§ 40—54). 
(Fig. XV. a.b.c. Archives of the Royal Society). Muscles of respiration in the Monkey 
(§§ 55, &c. 78). 
