Vol. IX, Nos. 8-9.] Biological Work of the ‘‘ Investigator.’ 365 
[N.S.] 
any alteration in the physical conditions present in the sur- 
roundings. 
In addition the results show that there is also an annual 
variation in the numbers of these 
surface : they are numerous during the months of November 
and December and then the numbers gradually diminish, so 
that at the beginning of February, they are comparatively 
During both seasons, daily observations were made on the 
surface temperature of these waters, and the results show that 
there is a very striking constancy in this respect : during the 
whole period covered by the observations, February to April 
1911 and December 1911 to February 19!2 the change in 
temperature never varied more than three degrees from 79° Ff. 
to 82° F., and in the vast majority of cases was between 80° 
and 81°. 
STOMATOPODA. é 
Alima and Erichthus larvae were present throughout the 
On tw 
fortunate enough to obtain specimens of a Discina larva : 
their occurrence is of considerable interest, for hitherto no 
examples of Discina have been found, as far as I am aware, by 
the RI.M.S. ‘« Investigator,’’ and further it shows that this 
species, like Lingula anatina, breeds in this region during the 
was obtained during the months of February to April, while 
Yatsu obtained a single specimen in Misaki Bay, Japan, be- 
tween June and September. : 
Both the present examples were, as is usually the case, 1n 
the 4 p. c. stage. 
EcuinoperMats.—-Ophiopluteus larvae were found to be of 
comparatively frequent occurrence at certa! 
the early part of the season, but as regards oth a ts 
the Phylum, larval forms were comparatively rare; In — 
