a correct System of Muscular Homologies. 317 
third in the left foot; of these the second, as indicated in the 
foot, is evidently the missing third-toe muscle, while the first 
may be the first-toe muscle, which is not otherwise mag 
If this be the case, the matter is still more clearly explicable in 
accordance with the type proposed above. In Dasyprocta the 
same authors speak of a palmaris brevis muscle attached to the 
palmar ossicle, but not connected with the digits, arising from 
the first and fifth metacarpal bones. This muscle is a back- 
ward prolongation of the type muscle, and evidently represents 
the accessorius of the foot; it is not present in the hare or 
rabbit, but in the guineapig it is distinctly traceable. A small 
muscle invests the flexor tendons still further forward in Agout?, 
similar to the flexor brevis manus, but which has no separate 
digital insertion; from the tendons themselves spring the 
lumbricales, three in number, as in the cavy, guineapig, 
rabbit, and hare: thus these three severed portions, if united, 
would constitute an accurate and typical flexor muscle of this 
series. In the human hand we find that this muscle, losing 
its bony origin, is connected to the palmar fascia on the inner 
side, and is known by the name of palmaris brevis, while its 
digital slips remain as the lumbricales. I have seen this 
muscle springing from the pisiform bone. Having thus traced 
this flexor series through its various mutations, we see that, 
despite its variability of form, it presents a constancy in its 
presence, and is sometimes developed in a high degree of com- 
plexity—for instance, in Nycticebus and the Lemuride in 
aE according to the illustrations of Messrs. Mivart and 
urie, and the text of Meckel, Vrolik, and others. We find 
in these animals :—first, a double set of ordinary lumbricales, 
one on each side of each finger; secondly, an accessory set, 
likewise in duplicate ; and, lastly, a third series, passing from 
the second to the third phalange of each digit: there are thus, 
as Meckel states, twenty-four muscles in all of this lumbrical 
Group 5 of these the first and second groups are only highly 
erentiated slips of the flexor brevis manus, while the last 
set may be continuations of the true dorsal interossei. 
The next groups of muscles in this segment are the inter- 
ossei, palmar and dorsal, devoted to the purpose of lateralizing 
the digits, the first series being flexors, and the second being ex- 
tensors. In the typical limb, where each digit has a vital indi- 
viduality of action, we should expect to find these muscles cha- 
racteristically and perfectly developed; but as in the limbs of 
most vertebrates, when possessing four or five digits, only one 
or at most two of them maintain this separateness of action, in 
the intermediate segments consolidation of the metacarpals or 
metatarsals interferes with independency of action ; still we find 
