270 W. F. E. WBLDON. 



EXPLANATION OF PLATE XXVII, 



Illustrating Mr. W. E. R. Weldon's Paper on a " Species of 

 Dinophilus Gigas." 



List of Reference Letters, 

 an. Anus. c.p. Cephalic ciliated pits. ci. Transverse ciliated baads. 

 B. Eye. e. gl. Gland cells of lips. gr. Granular cells of ectoderm, h. ph. 

 Horizontal diverticulum of pharynx. Tn. Intestine, l.m. Longitudinal muscle- 

 fibres. M.. Mouth, m.ph. Muscular appendix of pharynx, m. ep. Myo- 

 , epithelial cells of ectoderm. Me. Median lobe of gonad, ne. Position of 

 observed nephridia. n.f. Nerve-fibres, n. g. Nerve-cells, n.l. Lateral 

 nerve-cord. ce. (Esophagus, r. m. Circular muscles, st. Stomach, s. h. 

 Cephalic sense hairs, sh^. Post-cephalic rings of sense hairs, x. Deep cells 

 of cephalic ectoderm. Br. Brain. »S^, Stomodseal musculature. 



Figs. 1 — 10. — Dinophilus gigas. 



Fig. 1. The live animul extended, seen by transmitted light. 



Fig. 2. A specimen contracted by treatment with corrosive sublimate 

 solution, but not othervfise distorted. This figure shovrs fairly well the 

 shape assumed on irritation by the live creature. 



Fig. 3. A transverse section through the prse-oral lobe. 



Figs. 4 — 6. Transverse sections through the pharyngeal region. 



Fig. 7. The muscular bulb of the pharynx, in transverse section. 



Fig. 8. Section through the middle of the trunk. 



Fig. 9. Section through junction of stomach and intestine. 



Fig. 10. Section of ventral ectoderm. Zeiss's im., oo. 2. 

 Figs. 11 — 16. — Diagrams of various forms of pharyngeal apparatus, as 

 seen in longitudinal sections of the head. 



Fig. 11. Dinophilus (original). 



Fig. 12. Polygordius (schematised from Uhljanin). 



Fig. 13. Histriobdella (schematised from Foettinger). 



Fig. 14. Terebella larva (schematised from Saleusky). 



Fig. 15. Navis (schematised from Vejdovsky). 



Fig. 16. Vortex (schematised from von Graff). 



