1892.] Bacterial Investigation of ‘the Sea. 319 
Of the three most common mud forms found at Naples, the 
maximum depth limit of growth was not attained at the depth 
of 3500 ft. One of the three species (Cladothrix intricata) 
had nearly disappeared from the cultures, so that it was reas- 
onable to suppose that the bathymetrical range had been almost 
reached. The other two species were at this depth sufficiently 
Numerous to indicate that the maximum point of develop- 
ment had not been attained. This fact is of especial interest 
when we consider it in the light of the pressure experiments 
which have been carried out on bacteria. 
Our knowledge of the action of high pressure upon’bacterial 
metabolism is as yet imperfect, but there are several forms 
which seem to bear an increase of pressure of upwards of 100 
atmospheres without material change. 
A comparative study of the Mediterranean forms and those 
found on the New England coast gives an opportunity for a 
direct comparison from a specific as well as from a numerical 
standpoint. 
The work during the present season has been mainly con- 
fined to Buzzard’s Bay and Vineyard Sound off the Massa- 
chusetts coast, but through the kindness of Prof. Wm. Libbey, 
Jr, of the U. S. Fish Commission, samples of the mud 
Were obtained about 100 miles from the shore at the depth 
I 100 fathoms. They were taken by the schooner Gram- 
ee aa with bacterial life, to at least this distance from 
ore. . 
saan to be the same as those taken from near the ease 
a nage Holl. This proves a geographical dis 
la € common mud species for at least 100 miles from 
comparison of these forms with those at Naples 
— marked dissimilarity. The number of a 
Sige os the water and mud is not especially large in ee a 
“aie ne of the most interesting species found in aoe oe 
thrix ean endosporous, pseudo-branching form, Cla : 
— which was there quite frequent, but a ra 
at “ota Atlantic coast. This indicates that this species, 
» IS quite cosmopolitan in its distribution. Aside 
