12 H. W. MARETT TIMS. 
more closely to that of Trichechus than of Otaria, the Palmaris tertius in the former 
being much weaker than the other two heads. 
(v.) Flexor sublimis digitorum gives tendinous slips to all the digits, that to the 
pollex being the largest and the slip to the fifth digit being very small. This 
arrangement coincides with that found in Trichechus, though in the latter the fifth slip 
does not appear to be so much reduced. In this respect the condition in the seal is 
intermediate between Trichechus and Otaria, in which the slip to the fifth digit is 
wanting. Tendinous slips of insertion to all the digits seem to be exceptional among 
the land Carnivores, in which the slip to the fifth digit is usually absent. 
(vi.) Flexor carpi ulnaris.—Only the olecrano-pisiform portion of the muscle 
appears to be present; if there be any condylar fibres, they form but an insignificant 
part in these foetal animals. Here again this muscle is similar to that of Trichechus, 
in which there is no sharp division between it and the third Palmaris longus. 
In Otaria there is in addition a second strong tendon of insertion into the fifth 
metacarpal bone. 
Drs. Parsons and Windle give no instance of a Fissipede in which the olecrano- 
pisiform portion of the muscle is alone present, though the condition seems to be 
approximated in Procyon lotor, Ictonyx and Mustela putor. 
(vii.) Flecor brevis digitorum manus.—I could find no trace of this muscle, which 
I believe to be absent. In this respect this Seal agrees with the Otary and not with 
the Morse, in which this muscle is present. 
(vill.) Extensor communis digitorum gives tendons of insertion to all the digits 
with the exception of the first. They spring from a broad tendinous expansion lying 
over the dorsum of the metacarpals and blending with the fascia over the radial side 
of the manus. This is the usual carnivorous plan, but in this instance the tendinous 
expansion appears to be unusually large and strongly developed. A further point to 
notice is the presence of a tendinous intersection running for some distance up into 
the fleshy belly, into which the fibres on each side are inserted, giving a pectiniform 
arrangement, so commonly seen in the deltoid muscle. 
(ix.) Extensor profundus digitorum is inserted into digits 2, 3 and 4, the last 
being very feeble. The two outermost slips are inserted into the bases of the 
proximal phalanges, that to the second digit being prolonged onwards, reaching nearly 
to its distal end. A membranous expansion extends between the tendons, The 
condition of the outermost tendon seems to indicate approaching extinction. Absence 
of any slip to the pollex is a noticeable peculiarity on account of the relatively large 
size of that digit. 
(x.) Extensor ossis metacarpi pollicis.—I was unable to detect any origin from 
the radius. The groove on that bone for the tendon was comparatively deep. In 
origin this muscle agrees with Otaria, in which there is no radial origin, while in 
Trichechus the only bony origin is from the radius. 
Immediately subjacent to this muscle a long tendon was to be found which 
