1893. NOTES AND COMMENTS. 171 



In the January number of the Quayterly Jouynal of Microscopical 

 Scieme (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 Cephalodisciis and Balanoglossiis as 

 Protochordata with mouth ventral, and Avith no endostyle ; Ascidians 

 and Amphioxus, as having an endostyle and a dorsally-situated 

 mouth. In these two groups, Cephalodisciis is parallel with the 

 Ascidians. Both are sessile, possess a U-shaped alimentary canal, 

 have a small number of gill-sHts (one and three respectively), 

 and reproduce by buds. Balanoglossns and Amphioxus are also parallel, 

 being free-swimming, with straight alimentary canal, many gill-slits, 

 and without the power of budding. That difficult form, Appendicnlaria, 

 which was long regarded as the most primitive of the Ascidians, 

 Willey considers as a reduced and secondary derivative from the 

 Ascidian stock. 



The 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 j'ust 

 published the result of photographing a skate {Comptcs Rendus, vol. 

 cxvi., 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. M. 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-armounced discovery 

 by Professor W. A. Haswell {Proc. Linn. Soc. N.S. Wales, ser. 2, 

 vol. vii., 1892, pp. 197-199) is, perhaps, the most remarkable of its 

 iind. It is well-known that certain amoeboid 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, and appeared to be closely related 

 to the familiar Eii^lena. 



