1893. NOTES AND COMMENTS. 171 
In the January number of the Quarterly Fournal of Micyoscopical 
Science (vol. xxxiv., p. 317), Mr. Arther Willey has another interesting 
study on the ancestors of the Chordates. As the result of a series of 
observations, he groups together Cephalodiscus and Balanoglossus as 
Protochordata with mouth ventral, and with no endostyle; Ascidians 
and Amphioxus, as having an endostyle and a dorsally-situated 
mouth. In these two groups, Cephalodiscus is parallel with the 
Ascidians. Both are sessile, possess a U-shaped alimentary canal, 
have a small number of gill-slits (one and three respectively), 
and reproduce by buds. Balanoglossus and Amphioxus are also parallel, 
being free-swimming, with straight alimentary canal, many gill-slits, 
and without the power of budding. That difficult form, Appendiculania, 
which was long regarded as the most primitive of the Ascidians, 
Willey considers as a reduced and secondary derivative from the 
Ascidian stock. 
Tue application of photography to the study of animal locomo- 
tion is still being extended. M. Marey, we are glad to record, is 
continuing his observations on the swimming of fishes, and has just 
published the result of photographing a skate (Comptes Rendus, vol. 
‘XVi., pp. 77-81, Jan. 16, 1893). The body of the fish was firmly 
fixed, and the motion of the great pectoral fins was photographed 
from the side and from the front. The undulation of the fins proves 
to begin at the anterior border, and the whole progress of the motion 
bears a singular resemblance to the movements of a bird’s wing 
during flight. MM. Marey proposes now to devise means of studying 
the locomotion of the skate under natural circumstances, and will 
attempt to determine the extent and directions of the currents 
produced in the water. 
THERE are many strange phenomena connected with the life of 
protozoa within animal tissues, but a recently-announced discovery 
by Ptofessor W. A. Haswell (Proc. Linn. Soc. N.S. Wales, ser. 2, 
vol. vii., 1892, pp. 197-199) is, perhaps, the most remarkable of its 
kind. It is well-known that certain amceboid forms spend the whole 
of their existence within a single cell of the tissue of their host, 
and it is the ordinary rule among gregarines to begin life within a cell; 
but it now appears that even certain freely-swimming flagellate 
protozoa are capable of passing through life in a similarly restricted 
sphere. On examining a turbellarian worm from a pond in the 
neighbourhood of Sydney, Professor Haswell found one or more 
minute green flagellate protozoa in many of the cells. These were 
observed to be in an active state, andappeared to be closely related 
to the familiar Euglena. 
