Fig. 1. 
Prof. Owzw's Description of the Lepidosiren annectens. 357 
Tas. XXIV. 
Muscular System of the Lepidosiren annectens. 
a. Dorso-lateral series of muscles. 
b. Ventro-lateral series of muscles. 
c. Levatores pinnæ caudalis superiores. 
d. Levatores pinnæ caudalis inferiores. 
e. Levator scapule. 
J. Retractor scapule. 
g. Temporalis. 
h. Biventer, seu apertor oris. 
i. Mylohyoideus, seu constrictor branchiarum. 
The temporalis is an extremely powerful muscle, arising from 
the whole lateral part of the fronto-parietal bone, the median crest 
of which is developed for the purpose of increasing the surface of 
attachment, and consequently the bulk of the principal closer of 
the jaws. Small muscles pass from the ascending process of the 
upper maxillary to the under surface of the single intermaxillary 
bone, which they depress, and thereby serve to infix the sharp and 
slender intermaxillary teeth in the prey of the Lepidosiren. The 
analogue of the biventer mazille is a penniform muscle, and takes 
its origin from the upper and outer surface of the tympanic bone : 
it is inserted into the outer part of the lower jaw near the angle, 
and opens the mouth. Small choanoid muscles are attached to 
the base of the cartilage of each filamentary fin. 
a. a. Fibro-gelatinous ‘chorda dorsalis’. %. A portion of the central 
gelatinous part removed, leaving the fibrous capsule to which 
the ribs r.r. are attached. 
c. Bone representing the anchylosed anterior and posterior basi- 
sphenoid and basi-occipital bones. 
d. Pterygoid abutment, which is here a process of the superior maxil- 
lary arch. 
e. Cartilaginous pedicle and joint of the lower jaw, strengthened ex- 
ternally by the tympanic bone. 
