544 ORESSWELL SHEARER. 



DESCRIPTION OF PLATES 29 & 30, 



Illustrating Mr. Cresswell Shearer's paper ou "The Structure 

 of the Nephridia of Diuophilus.'^ 



Lettering. 



bid. Blastococlic spnce of the head segment, i/c.2. Elasloccelic space of 

 the trunk rej^ioii. bas.mem. Basement membrane of tlie epidermis, e.f/r. 

 Excretory granules of the blastocoelic spaces, fgl. Piageila of the nepliridial 

 canal. Jig. Flagellum of a solenocyte. (jr.s. Granule in tlie head of the 

 solenocyte. Gt. Gut. msc. Muscle fibres, m.v. Limiting membrane of the 

 vesiculse. nep.c.'i. Second portion of the nephridium. nep.c.'i. Third por- 

 tion of the nephridium. pig.str. Pigment cells, phr. Pharynx, phr.o. Pha- 

 rynx organ, sep.d. Line of division between segments, sol. Soleuocytes. 

 sp.m. Sperm reservoirs or spaces of the testis. Stm. Stomach. Tes. Testis. 

 vac. Vacuoles of the epidermis, v.c. The ventral thickened crawling surface 

 of the worm. vesc. Vesicula seminalis. 



PLATE 29. 



Figs. 1 — 12 were drawn under a 2 mm. oil-immersion obj. with oc. 

 G, except M'here otherwise indicated. They were drawn from living 

 preparations, although no attempt has been made to exactly portray the 

 appearance of the living protoplasm, which is sim))ly roufihly indicated as 

 granular. The sections are from material treated with cocaine and fixed in 

 Hermann's fluid and Zenker's fluid. 



Pig. 1. — A portion of the first nephridium, somewhat unduly compressed 

 and flattened. Obj. 2 mm., oc. 12. 



Pig. 2. — A solenocyte of the third nephridium. Obj. 2 mm., oc. 18. 



Pig. 3. — The second nephridium. Several granules being seen in the 

 blastococlic space about the gut. 



Pig. 4. — The second nephridium. 



Pig. 5. — The first and second portion of the third nephridium. 

 Pig. 6. — A portion of the flagella of the third nephridium. 

 Pig. 7. — The termination of the canal of the third nephridium in the base- 

 ment membrane of the epidermis. Obj. 2 mm., oc. IS. 

 Pig. 8. — Head portion of the third nephridium. 



