THE ADIPOSE LOBE OF THE PELVIC FIN OF THE SALMON. 781 
(see fig. 1), they may act as dams to prevent the back-wash of 
water, which would be considerable in a fish with large 
pelvics, and so facilitate the swift motion through the water 
for which the salmon is noted. 
EXPLANATION OF PLATE 43, 
Illustrating Mr. Edward W. Shaun’s paper, ‘^An Account 
of the Anatomy and Homology of the Adipose Lobe of the 
Pelvic Fin of the Salmon.” 
Lettering. 
Ad. Adipose lobe. B. m. Basale metapterygii. C. t. Connective 
tissue. Cm. Cutis. Ejp. Epidermis. F. r. d. Dorsal haK of a fin-ray. 
F. r. V. Ventral half of a fin-ray. Fi. Fat- globules. Ft.' Fatty tissue 
from which the fat has been extracted with alcohol. M. Muscle. M. h. 
Membrana basale. N. Nuclei. Pig. Pigment-cells. Pt. Pterygiophores. 
Sc. Body-scale. Sc. a. Accessory scale. Sc. p. Scale iiocket. Sp. Splint 
of bone which supports the adipose lobe. Sp. h. Hole caused by the 
removal of the splint of bone which supports the adipose lobe. V. f. 
Ventral (pelvic) fin. 0., Jj., V. Outer, dorsal, and ventral aspects. 
Fig. 1. — A portion of the right side of a Wye salmon showing the 
2 )elvic fin ; a piece of black pasteboard has been placed beneath the 
adipose lobe to render its outline more distinct. Photogi-aiih by Mr. 
.T. T. Wadsworth, Manchester. X -|. 
Fig. 2.— Skeleton of the right pelvic fin of a Wye salmon, seen from 
the ventral aspect; the rays are siiread out and separated from the 
Basale metapterygii, with which in the natural condition they 
closely articulate. The numbers refer to the lexiidotrichia. Photo- 
graph by Mr. A. W. Brown, St. Andrews. Slightly reduced. 
Fig. 3.— Transverse section of the adipose lobe, abou tone third of the 
length from the basal end, together with the adjacent body- wall. Fi-om 
a Rhine salmon, whose adipose lobe measured 35 mm. by 6 mm. The 
sections, of which this is one, were block-stained iron-hsematoxylin, and 
cut 30 ju thickness. 
Fig. 4. — Transverse section of the adipose lobe at the base (the lobe 
is quite continuous with the body-wall). Rhine salmon, dimensions 
not kno^vn. Method of xirexiaration as above. 
