308 E. A. MINCHIN. 



EXPLANATION OF PLATES XXVII & XXVIII, 



Illustrating Mr. E. A. Minchin's '' Observations on the 

 Gregarines of Holothurians." 



PLATE XXVII. 



All the figures on this Plate refer to Gregarina irregularis, n. sp., 

 inhabitiug Holothuria nigra. 



Fig. 1. — A specimen from the blood-vessels, drawn living. 



Fig. 2. — Another specimen from the blood-vessels. Flemming's fluid, 

 borax carmine. Zeiss, compens. ocular 4, obj. B, camera lucida. X 128. 



Fig. 3. — Section (from a series of 40 sections, the 15th of the series) 

 through a blood-vessel with the contained Gregarine. Kleinenberg's picric, 

 hsematoxylin. Zeiss, compens. ocular 4, obj. B, cam. luc. X 128. 



Fig. 4. — The inner part of Fig. 3, x 315. Zeiss, compens. ocular 4, 

 obj. D, cam. luc. 



YiG. 5. — Another section (34th of the series) passing through the other 

 nucleus of the same Gregarine. Zeiss, compens. ocular 4, obj. D, cam. luc. 

 X 315. 



Fig. 6. — The section (33rd of the series) immediately before that drawn in 

 Fig. 5. Ocular and objective as in the last figure; cam. luc. x 315. 



Fig. 7. — The section next but one before the last (31st of the series). 

 Ocular and objective as in the last figure ; cam. luc. x 315. 



Fig. 8. — Section through another blood-vessel and the contained Gregarine 

 (from a series of 96 sections, 85th of the series), Zeiss, compens. ocular 4, 

 obj. D, cam. luc. X 315. 



Fig. 8«. — The nucleus from the same section. Compens. ocular 4, obj. F, 

 cam. luc. X 730. 



Fig. 9. — One of the stalked vesicles, containing a cyst, from the blood- 

 vessels, as seen living. Drawn with Zei:s, oc. 2, obj. B. 



Fig. 9«. — The edge of the same in optical section. Oc. 2, obj. D. 



Fig. 10. — A portion of the blood-plexus, with a cyst attached. 



Fig. 11. — The contents of a cyst teased up. a. Drawn living. b,f. Fixed 

 with picric-osmic-acetic mixture, and stained with Kleinenberg's hsematoxy. 

 lin. Zeiss, compens. ocular 4, obj. F, cam. luc. X 730. a, b, and c. Spore- 

 blasts, each with a single central nucleus. d,f. Nucleated masses of proto- 



