Manrcw 8, 1901. ] 
also considered, and the coefficient of the 
net shown in the plottings of the rating ex- 
periments. Experiments without a meter 
were also used to demonstrate that the 
efficiency of Hensen’s net had not been 
diminished, but rather increased by the 
addition of the brass cylinder and meter at 
the net opening. 
As prominent factors in determining the 
efficiency of the net were mentioned the 
size of the orifice, and the ratio between the 
area of the orifice and the area of the filter- 
ing surface. Various. details in improve- 
ments of apparatus were mentioned, and 
the laboratory of the United States Fish 
Commission at Put-in-Bay, together with 
the steamer and apparatus used and the 
records obtained, were illustrated from lan- 
tern slides. 
A New Method of Reproduction in Tubularian 
Hydroids: C. C. Nurrine. 
The meduse of Hybocodon prolifer were 
found to be reproducing by means of acti- 
nules formed onthe manubrium. The proc- 
ess of development of the actinules was 
described, and the intergradation between 
this process and the production of actinules 
in the gonophores of ordinary tubularians 
was traced through a series of forms includ- 
ing Tubularia spectabilis (Agassiz), Tubularia 
cathouyt Ag., and Oorymorpha pendula Ag. 
The paper was illustrated by charts pre- 
pared by the author. 
Remarks on the Distribution of Hydroida on the 
North Pacific Coast; C. C. Nurrine. 
The basis of this paper was a study of the 
Hydroida of the Harriman Alaska Expedi- 
tion. The division of the Pacific Coast 
fauna made by Dall in 1876 was found tobe 
untenable in the light of our present distri- 
bution of the hydroids. It was shown that 
there was no marked differentiation between 
his Aleutian and Oregonian faune, on the 
one hand, and that the Oregonian fauna 
does not extend to Monterey, California, 
SCIENCE. ; 3tT 
on the other. The facts seem to indicate a 
division between an Alaskan and a Cali- 
fornian province just south of Puget Sound. 
The author pointed out that this arrange- 
ment was only tentative, and that the dis- 
tribution of other groups of marine animals 
of that region would be necessary before any 
conclusive statement could be made. 
The Holothurians of the Pacific Coast of North 
America: H. L. Crarx. 
The examination of 52 specimens, repre- 
senting 11 species, from Pacific Grove, Cal- 
ifornia, has thrown considerable light on the 
holothurians of the Pacific Coast. The oc- 
currence of three species (Synapta inhe- 
rens, Oucumaria calcigera, Psolus squamatus) 
which also occur on the Atlantic Coast 
would seem to indicate that these species 
either are now, or have been, circumpolar 
forms with southward prolongations of 
their range on the east and west sides of 
the continent. The most interesting feature 
of the collection is the occurrence of three 
new species, all of which show some peculi- 
arity in the manner of caring for the 
young. A small, black Cucumaria broods 
its eggs and young, while a small, red 
Thyone is viviparous, the young being found 
in the body cavity of the mother, asin Sy- 
naptavivipara. The most remarkable species, 
however, is the representative of a new 
genus, Thyonepsolus, which is perfectly inter- 
mediate in character between Thyone and 
Psolus, having the ventral surface flattened 
to a creeping sole covered by a thin skin, 
while the dorsal surface is convex and soft. 
On the sole the feet are in three longitudinal 
rows, while dorsally they are numerous and 
irregularly scattered. The young are car- 
ried on the back of the mother, partially 
imbedded in the thick, soft skin. 
Structure of Clinostonum (Preliminary no- 
tice): Henry L. Osporn. 
The finding of Clinostomum at Neebish, 
Chippewa Co., Michigan, in August, 1900, 
