450 MR. P. H. GOSSE ON THE STRUCTURE, FUNCTIONS, AND HOMOLOGIES 
Explanation of the Plates. 
PLATES XVI., XVII., XVIII. 
The figures of considerable portions of animals, are magnified 220 diameters ; those 
of the details were taken with a power of 560 diameters, but are not drawn to scale. 
The following letters of reference indicate the same organs, or their representa- 
tives, in all the figures in which they occur: — 
a. Mastax. 
h. Malleus. 
c. Manubrium. 
d. Articulation. 
e. Uncus. 
f. Incus. 
g. Ramus. 
h. Fulcrum. 
i. Muscle, connecting the uncus with 
the ramus. 
y. Muscle for extending the malleus. 
k. Muscle for bending the malleus. 
l. Muscle for throwing-in the manu- 
brium. 
m. Buccal funnel. 
n. Salivary glands. 
o. Alula. 
p. CEsophagus. 
q. Dorsal process of uncus. 
r. Labrum. 
s. Pancreatic glands. 
Muscular bands proceeding from the 
u.\ alulae, helping to open the rami. 
V. Domular structure in funnel. 
X. Eye. 
y. Ganglion. 
z. Nervous chords. 
Fig. 1 . Brachionus urceolaris : mastax and dental apparatus ; ventral aspect. 
Fig. 2. Brachionus urceolaris : jaws ; viewed nearly from above. 
Fig. 3. Brachionus urceolaris : malleus, flattened by pressure. 
Fig. 4. Brachionus urceolaris'. the same; as it appears during life. 
Fig. 5. Brachionus urceolaris'. mastax and dental apparatus; lateral aspect. 
Figs. 6, 7, 8. Brachionus urceolaris : manubrium ; illustrating its changes of position 
during action. 
Fig. 9. Brachionus urceolaris : buccal funnel, salivary glands, mastax, and dental 
apparatus ; dorsal aspect. 
Fig. 10. Brachionus ruhens : incus; lateral aspect. 
Fig. 11 . Metopidia acuminata', showing the frontal plate. 
Fig. 12 . Euchlanis dejlexa: buccal funnel, mastax, dental apparatus, oesophagus, and 
salivary glands ; dorsal aspect. 
Fig. 13. Euchlanis dejlexa'. mastax and dental apparatus, after potash-treatment; 
lateral aspect. 
Fig. 14. Euchlanis dejlexa'. the same ; frontal aspect. 
Fig. 15. Euchlanis dejlexa'. the same; viewed dorsally, and nearly frontally. 
