DR. J. MURIE ON THE MANATEE. 33 
down, in part lying upon and in part commingling with the flexor carpi ulnaris, runs 
on to the outside of the fifth digit, and is inserted by tendon on the distal outer margin 
of the fifth metacarpal. The muscle in question is apparently supplied by a branch of 
the ulnar nerve; at least I traced the nerve under its belly, though an awkward slip of 
the scalpel prevented my assurance of its entrance into the muscle. ‘To all intents and 
purposes the muscle now described is representative of a palmaris longus or of an 
unusually developed flexor brevis minimi digiti. If it is the latter, then what may be 
combined palmaris longus and flexor carpi ulnaris obtain in this example, as has been 
hitherto described. 
As to the sublimis and profundus flexors in common, their muscular origin reaches 
quite and even beyond the wrist. LDistally, but superficially, it is tendinous, viz. from 
the lower third of the arm-bones. As freshly examined, the digital tendons go to the 
ends of the second, third, and fourth proximal phalanges, beyond which they form uni- 
form, stout, aponeurotic coverings to the fingers. Between the wrist and ends of meta- 
carpals tendons representing perforans and perforatus are easily distinguishable. More- 
over the subjacent longest-continued fleshy belly has its fibres slightly athwart, and 
minute tendons underneath, chiefly distributed to the third and fourth digits. A longus 
pollicis is not distinct, unless that tendon, going to the second digit, represents it. 
There is a single distinct lumbrical muscle (/, fig. 4) which arises from the wrist-fascia, 
and, with a comparatively long fleshy cord, is inserted into the tendon of the fourth 
digit. In its course it passes but slightly from the radial towards the ulnar side of 
the palm. 
As to the remarkable interossei, clearly in this example the superficial fleshy layer 
cannot be considered lumbricales, as suggested by me in my former paper, a single 
lumbrical muscle existing superficially as just described. Again, it is very questionable 
if the superficial layer is an anomalous flexor brevis manus, as also formerly hinted. 
The flexor brevis manus, as originally described by Prof. Mivart and myself in the 
myology of Hyrax', had a position superficial to the flexor sublimis and profundus, 
instead of deeply to those muscles, as in this case; and both origin from the palmar 
fascia and tendons of insertion differ. 
I may describe the interosseal arrangement in this Manatee, as it varies from that of 
the previous occasion2. Of the superficial set from the inner radial tuberosity and the 
carpus there arises a strong mass of fleshy and tendinous substance,which thereafter divides 
into three somewhat fusiform divisions, inserted respectively on the sides and proximal 
ends of the proximal phalanges. One division goes to the ulnar side of the second 
digit and to the radial side of the third; another division, the middle one, ends on the 
sides of the third and fourth digits; and the third division is fixed respectively to the 
neighbouring sides of the fourth and fifth digits. The deep interossei are relatively 
powerful and almost altogether fleshy. They agree with what I obtained on the former 
1 Proc. Zool. Soc. 1865, p. 342, fig. 6. ? Trans. Zool. Soc. vol. viii. p. 161, pi. xxii. figs. 13 & 14. 
