AGASSIZ AND ^VOODWORTH : VAKIATIONS IX 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 Medusae and Ctenophora, a Zeiss series 

 11." 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 camera 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, PI. IV. Fig. 4, PI. V. Fig. 5. 1849. 

 Sarsia. 



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 Tentaculocysts of Aurelia aurita. Quar. Jour. Micr. 

 Sci., Vol. XXXVII. Pt. 3, pp.' 245-251, PI. XXV. 1S95. 

 Brown, E. T. 

 Ou Variation of Haliclystus octoradiatus. Quar. Jour. Micr. Sci., Vol. 

 XXXVIII. Pt. 3, pp. 1-8, PI. I. 1895. 

 Claparede, Ed. 

 Beobachtuugen iiber Anatomie uud Entwicklungsgeschichte Wirbelloser Thiere, 

 p. 5. Leipzig, 1863. Eleutheria. 



Ehrenberg, C. G. 



Ueber die Akalephen des rothen Meeres uud den Organismus der Meduseu 

 der Ostsee. Abhandl. Akad. Wiss. Berlin, 1835, pp. 199-202, Taf. I., II. 

 Berlin, 1837- Aurelia, Stomobrachium. 



