56 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA. 



17. 1904-8. Graff, L. vox. Das Thierreich, Turbellaria. I. 



Acoela und Bhabdocoelida. 



18. 1907. Hofsten, Nils von. Studien iiber Turbellarien aus 



dem Berner Oberland. Zeitschr. f. wiss. Zoologie, 

 lxxxv., pp. 391-654. 



19. 1908. Martin, C. H. Notes on some Turbellaria from the 



Scottish Lochs. Proc. Roy. Soc. Edin., vol. xxviii., 

 pp. 28-34. 



20. 1908. Ibid. The Nematocysts of Turbellaria. Quart. 



Journ. Micro. Sci., vol. lii., pp. 261-277. 



21. 1908. Southern, R. Handbook to City of Dublin. Brit. 



Assoc. 



22. 1909. Graff, L. von. Die Siisswasserfauna Deutschlands. 



Heft. 19. 



23. 1911. Ibid. Acoela, Bhabdocoela und Alloeocoela des ostens 



der vereinigten staaten von Amerika. Zeitschr. 

 wiss. Zoologie, xcix., pp. 1-108. 



24. 1912. Southern, R. Clare Island Survey. Pt. 56. Platy- 



helmia. Proc. Roy. Irish Acad., xxxi. 



Description of Plate 4. 



Pig. 1. Dalyellia viridis, entire, x 15. 



2. Chitinous copulatory organ of D. viridis, X 150. 



3. Microstomum lineare, entire, x 20. 



4. Mesostoma sp., entire with thin-shelled eggs, x 20. 



5. Gyratrix hermaphroditus, entire, X 45. b c, bursa copu- 

 latrix ; c, cocoon ; c p, ciliated pit ; e, egg ; g, gut ; 

 m, mouth ; o v, ovary ; p, poison-sac ; p h, pharynx ; 

 p r f proboscis ; s t, stiletto ; it t, uterus. 





Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



