1912] Ritter: The Marine Biological Station of San Diego 199 
partly descriptive but chiefly experimental (Torrey, 1905a) he 
‘ 
concludes that the facts ‘‘appear to give strong support to the 
view that the stem [of the hydroid Clytia bakeri] instead of 
retaining unmodified its regenerative capacity, actually loses 
with age its ability to produce structures which formerly char- 
acterized it; and that this is owing to a modification of con- 
ditions within the organism, which govern its behavior without 
being necessarily a part of it.’’ And further that ‘‘the resem- 
blance of the phenomena of colonial differentiation in C. bakeri 
to the phenomena of senescence is so strong as to suggest a similar 
interpretation for both.”’ 
Of his series of studies upon the fine large hydroid Cory- 
morpha palma, Dr. Torrey has devoted one (1910c) to the much 
investigated phenomena of heteromorphosis and of polarity. 
Complete reversal of polarity of pieces cut from the stem was 
observed, and a considerable measure of control was effected 
over the phenomena, both as to occurrence itself and as to the 
rate of growth. For example it was shown that by inserting 
the distal end of a section of the column into a capped glass 
tube, a hydranth promptly develops at the free or proximal end 
of the piece, but not at the end in the tube; whereas a similar 
piece not enclosed in glass develops distal but not proximal 
hydranths. The author believes exclusion of oxygen by the glass 
tube explains the difference in results. 
Torrey and Mery (1904) have considerably enlarged our 
information about asexual propagation in the anemones, three 
rather distinct modes of fission having been observed in the same 
species. In the species studied another instance of hetero- 
morphosis is recorded for the group, of which until now con- 
paratively little has been known. 
Number II of Torrey’s studies on Corymorpha (1907a) is 
devoted to the embryonic development of the animal. This 
species appears to be peculiar in its genus in that the egg-carry- 
ing medusae do not become detached from the hydroid. Eeg- 
laying occurred in May, June, July, August, September, Decem- 
ber, and January, no observations having been made in the 
remaining months of the year. From this standpoint as well as 
from several others, the animal is well fitted for biological 
