164 J, (). WAKKLIN BARKATT AND GEOiiGK ARNOLD. 



6. Lim Boom Keng. — " On the Ccelomic Fluid of Liimbricus 



terrestris in reference to a Protective Mechanism," 'Philo- 

 sophical Trans, of the Roy. Soc. of Lond.," 1896, B, vol. clxxxvi, 

 p. 383. 



7. Benham, W. Blaxhmd. — " The Cojlomic Fluid in Acanthodi-ilids," 



' Quart. Journ. Micr. Sci.,' 1901, vol. 44, p. otjo. 



8. Hollande, A. C. R. — " Contribution a I'etude du sang des Coloop- 



teres," ' Archives de Zool. experimentale at generale,' 1909, t. 2. 

 p. 271. 



9. Cf. Leydig. ' Untersuchungen zur Anatomie und Histologie der 



Tiere,' 1884, and ' Zelle und Gewelje,' 1885 ; C. v. Wistinghausen, 

 ' Ueher Tracheenendigungen in den Sericterien der Raupen." 

 • Zeit. f. wiss. Zool.,' 1890, vol. xlix, p. 565. Also Packard, ' Text- 

 l)ook of Entomology,' 1898, -p. 435. 

 10. Quoted by Packard, loc. cit.. pp. 419-423. 



EXPLANATION OF PLATE 11, 



Illustrating the paper by Dr. J. 0. Wakeliu Barratt and Mr. 

 Geoi-ge Arnold entitled "A Studj' of tlie Blood of certain 

 Coleoptera : D y t i s c u .s m a r g i n a 1 i .s and H y d v o p li i 1 u s 

 pice us." 



[The drawings are made using a 2 mm. Mpochromatic oil-immersion 

 objective with 8 and 18 compensating oculars, are drawn without the 

 aid of a projection apparatus, and ai-e i-epresented as stained by 

 methylene-blue and orange G. Magnification 1250 diameters. 



Figs. 1-9.— Dy tiscus. Phagocytic cells are represented in figs. 1-8; 

 small round-cells in fig. 10. 

 Figs. 1-3. — Phagocytic cells in the active condition with p«eudopodia. 

 Figs. 1 and 3 viewed from above ; fig. 2 seen on edge. Nucleus entire, 

 chromatin inconspicuous. Cytoplasm contains no food-vacuoles in 

 figs. 1 and 3. 



Fig. 4. — Phagocytic cell with recently ingested particles of Indian 

 ink in the cytoplasm. Vacuoles have not yet formed roiind the particles. 



Fig. 5.— Phagocytic cell exhibiting amitotic division, nearly com- 

 pleted. 



Figs. 6 and 7.— Phagocytic cells exhibiting active digestion. In 

 fig. 6 the ingested matter is in close contact witli, and depressing, the 



