1885.] Psychology. 519 
Finally, it may be said that the rudimentary tibia, when present, 
is directed backward in the cetaceans just as in pinnipeds, show- 
ing that if it were fully developed and prolonged it would carry 
the pedes far behind a vertical line drawn through the hip-joint. 
There is also other evidence that the inclusion of the hind limbs 
in the whales has occurred in much the same way as in pinnipeds, 
for example, the femora are adducted to a remarkable degree in 
Balena, according to Struthers, showing that the encroachment 
of other parts must have been the principal cause of such adduc- 
tion. The femora of Halitherium seem also to have been direct- 
ed backward toward the flukes, according to the figures given by 
Lepsius. 
The translocation of the pedes of cetaceans has been accom- 
plished through an extended phyletic series and was not sudden 
or partially saltatory as in the case of the pelvic limbs of embryo 
physoclists. The translocation in the first case was due to the 
ackward extension of the limb, outwardly carrying only the pes 
away from its original place, in the latter the whole limb is shifted 
together with the girdle. In cetaceans there has been little or no 
shifting of the pelvic girdle, its detachment from the vertebral 
column being due to the atrophy of the ilium. The extension 
backwards of the limbs and pedes parallel with the caudal portion 
of the vertebral column, obviously began in an amphibious mam- 
malian type and has thus gradually brought the pedes to their 
present position, where they appear ontogenetically; heredity, 
through immediate ancestry, here, as in many other cases, greatly 
marring the phylogenetic record. This gradual shifting, accord- 
ing to the method described, completely does away with the diffi- 
culty suggested by Flower as to the helplessness of the animals 
during the transfer, which really began in forms already to a 
great extent helpless on land but certainly not in the water. 
The foregoing gives the principal anatomical and embryologi- 
cal grounds for regarding the flukes of Cetacea as the representa- 
tives of pedes translocated backward by rotation and extension 
of the limb rearward into a position parallel with the tail by the 
process of inclusion as described above, but as it is impossible to 
consider the evidence in favor of this conclusion in detail in this 
brief abstract, those interested are referred to my illustrated 
memoir on the subject almost ready for publication by the U.S. > 
Fish Commission.—/ohn A. Ryder. 
PSYCHOLOGY. 
INTELLIGENCE OF THE Limpet.—By far the larger number of lim- 
pets “roost” upon rocks whose only covering consists of minute 
green alge and millepores, together with numerous acorn barn- — 
acles. These last are seen to be of very unequal degrees of “ clean- 
ness,’ some being covered with vegetable growth, others quite 
white and bare. Those immediately surrounding a limpet or group 
