630 W. S. PERRIN. 
9. 1904. Woopcocx, H. M.—‘* Myxosporidia in Flat Fish,” Herdman’s 
Report on the Lancashire Sea Fisheries Scient. Inv. f. 1903, ‘ Trans, 
Biol. Soc. Liverp.,’ vol. xviii, 1904. 
10. 1904. Woopcocx, H. M.—‘‘ Note on a Remarkable Parasite of Plaice 
and Flounders,”’ ibid. 
11, 1904. Street, W.—“ Uber Nosema anomalum (Monz),” ‘ Archiv 
f. Protist.,’ iv Bd., 1 Hft., 1904, p. 1. 
EXPLANATION OF PLATES 37 & 38, 
Illustrating Mr. W. 8. Perrin’s paper on “ Observations on 
the Structure and Life-history of Pleistophora peri- 
planet, Lutz and Splendore. 
All the figures refer to Pleistophora periplanete from the Malpighian 
tubules and gut of Periplaneta orientalis with the exception of Figs. 21, 
22, 23, 24, and 37, which refer to another Myxosporidian parasite from the 
same locality. 
The figures are all drawn with the help of Zeiss’s drawing camera from 
stained preparations. Those upon the left half of the plate are drawn and 
coloured from preparations stained with Giemsa’s eosin-azur. Nuclear struc- 
tures are in all cases tinged a bright red or purple and protoplasm a bright 
biue. The remaining figures are drawn from preparations stained with 
Delafield’s hematoxylin, with the exception of Fig. 28, which was stained by 
Heidenhain’s iron hematoxylin method. 
A Zeiss microscope with an apochromatic 3 mm. homogeneous oil immersion 
objective (mm. ap. 1°40) and compensating eye-pieces 12 and 18 was used in 
all cases. 
Critical illumination with strong artificial light, Welsbach incandescent, 
etc., was employed. 
Magnifications.—Figs. 1—32, 34—37, 50, 51: 1750/1. 
Figs. 383, 388—49: 2700/1. 
PLATE 37. 
Fires. 1 to 8.—Series of trophozoites of increasing size and with nuclei 
ranging from one to eight in number, Fig. 4 shows a trophozoite with three 
nuclei, one of which is in process of division, The series illustrates the 
development of a multinucleated plasmodium from a uninucleated sporozoite. 
Fic. 9.—Multinucleated trophozoite with reticular protoplasm and numer- 
ous vacuoles. The nuclei are of two kinds, the more numerous variety being 
