AGASSIZ AND WOODWORTH: VARIATIONS IN EUCOPE. 145 
means of an adapter. The light in this case was centred upon the 
substage mirror of the microscope, and thus upward. Jellyfish that 
have been for some time in a small quantity of sea water become par- 
tially stupefied by the consumption of the air in the water, and are then 
more quiet and their tentacles are better extended. 
For larger objects, such as Medusi and Ctenophora, a Zeiss series 
IL* 1:8 photographic lens with an iris shutter was made use of. A 
reversing prism fastened to the front of the lens allows the use of a 
horizontal eamera in photographing animals in open dishes. Work of 
this description is done out of doors, illumination being obtained by a 
series of mirrors, the arrangement of which varies with the nature of 
the object and the view desired. The work is still in an experimental 
stage, and it is hoped to give in a subsequent paper a more detailed 
account of methods and results. 
The following authors have noted variations in Acalephs :— 
Agassiz, L. 
Contributions to the Natural History of the Acalephs of North America. 
Mem. Amer. Acad., Vol. IV. p. 248, Pl. IV. Fig. 4, Pl. V. Fig. 5. 1849. 
Barsia. 
Bateson, W. 
Materials for the Study of Variation, pp. 424-429. London, 1894. Aurelia. 
Brown, E. T. 
Aurelia aurita: Numerical Variation. Nature, Vol. L. No. 1300, p. 524. 
1894. 
Brown, E. T. 
On the Variation of the Tentaculoeysts of Aurelia aurita. Quar. Jour. Mier. 
Sci., Vol. XXXVII. Pt. 3, pp. 245-251, Pl. XXV. 1895. 
Brown, E. T. 
On Variation of Haliclystus octoradiatus. Quar. Jour. Mior. Sci., Vol. 
XXXVIII Pt. 8, pp. 1-8, Pl. I. 1890. 
Claparede, Ed. 
Beobachtungen über Anatomie und Entwicklungsgeschichte Wirbelloser Thiere, 
p. 5. Leipzig, 1803. — Eleutheria. 
Ehrenberg, C. G. 
Ueber die Akalephen des rothen Meeres und den Organismus der Medusen 
der Ostsee. Abhandl Akad. Wiss. Berlin, 1835, pp. 199-202, Taf. I., II. 
Berlin, 1837. Aurelia, Stomobrachium. 
