356 ALPIIED GIBBS BOURNE. 



DESCRIPTION OF PLATES XXVI & XXVII, 



Illustrating Professor Alfred Gibbs Bourne's '' Notes on the 

 Naidiform Oligochseta/' &c. 



PLATE XXVI. 



Fig. 1, — Surface view of Pterostylarides macrochaeta. The seg- 

 ments are numbered 1 — 28. m. Mouth. 



Fig. 2. — View of Paranais littoralis. The Arabic numerals indicate 

 segments of the parent worm ; the Roman numerals are attached to segments 

 in the budding zone. m. Mouth, 'ph. Pharynx, ph. gl. Pharyngeal glands. 

 st. Stomach. A. v. Dorsal vessel, v. v. Ventral vessel, int. Intestine. 

 n. Nerve-cord. 



PLATE XXVII. 



Fig. 3. — Anterior extremity of a sexual individual of Paranais lit- 

 toralis. fh, gl. Pharyngeal glands, gen. set. Genital seta bundles, sp. 

 Spermatheca. t. Testis, ov. Ovary. 



Fig. 4. — Ventral seta from segment ii, iii, or iv, of Paranais littoralis. 



Fig. 5. — Modified genital seta of Paranais littoralis. 



Fig. G. — Dorsal seta from Paranais littoralis. 



Figs. 7, 8, and 9. — Views of the budding zone in Stylaria lacustris in 

 successive stages of growth. Z. Budding zone. z. Newly budded tail. 

 «'. Newly budded head. pr. New prostomial tentacle. The Arabic numerals 

 indicate segments of the parent worm ; the Roman numerals indicate newly 

 budded segments. Fcec. Faeces, showing how they pass through the newly 

 budded region. 



Fig. 10. — Enlarged view of the seta bundles of one side of the new head, 

 from the same specimen as Fig. 9. 



Fig. 1]. — Diagram of the anterior extremity of Pristina breviseta. 



Fig. 12. — Diagram of the budding zone of Pristina breviseta. Letters 

 and numerals as in Fig. 9. The animal is drawn from the side to show the 

 dorsal and ventral seta bundles. 



Fig. 1.3. — Ventral seta of Pristina breviseta. 



Figs. 14 and 15. — Capillary and spear-shaped dorsal setse of Pristina 

 breviseta. 



