20 
THE ESSEX NATURALIST. 
(30.) Pearl, Raymond (1906), The movements and reactions of Fresh¬ 
water Planarians, A Study in Animal Behaviour. Q. J. Micros. 
Science, vol. 46, p. 509 -f- 
(31.) Ritchie, John, junr., A Contribution to the Parasitic Fauna of the 
West of Scotland. Glasgow Naturalist, vii. (No. 2), 1915, pp. 33- 
42. 
(32.) Shaw, G. (1791), Description of the Hirudo viridis, a new English 
Leech. Trans. Linn. Soc., i., pp. 93-95, pi. vii. 
(33.) Southern R. (1908), Handbook of City of Dublin. Brit. Assoc. 
(34.) Southern, R. (1912), Clare Island Survey, Part 56, Platyhelmia. 
Proc. Roy. Irish Acad., xxxi. 
(35.) Steinmann, P. (1908), Arch. Sci. Phys. Nat., xvi., pp. 552-3. 
(Regeneration.) 
(36.) Steinmann, P. und Bresslau, E. (1913), Die Strudelwurmer (Tur- 
bellaria). Band 5, Monographien einheimischer Tiere. Herausgege- 
ben von Prof. Dr. H. E. Ziegler und Prof. Dr. R. Woltereck. 
(37.) Stoppenbrinck, F. (1905), Die' Geschlechtsorgane der Siisswasser- 
tricladen in normalen und in Hungerzustande, Zeitschr., fiir. wis- 
sensch. Zoologie, lxxix., pp. 496-547, 1 pi., 1 fig. 
(38.) Voigt, W. (1904), Ueber die Wanderungen der Strudelwurmer in 
unsern Gebirgsbachen. Verb, naturhist. ver. d. preuss. Rheinlande, 
61, pp. 496-547 (1 pi., 1 fig.) 
Fig. 1. 
2. 
3 - 
4 - 
5 - 
6 . 
7 - 
8 . 
9 - 
10. 
11. 
EXPLANATION OF PLATE I. 
Dendrocoelum lacteum. Diagrammatic representation of internal 
structure observable by a lens in transparent specimens. 
Bdellocephala punctata. 
Planaria alpina. 
PI. gonocephala. 
PI. polychroa. 
PI. torva. 
Polycelis cornuta. 
P. nigra. 
Part of genitalia of Planaria polychroa. 
,, ,, PI. torva. 
Transverse section of PI. alpina through the’ r pharynx. 
. 12. 
Longitudinal section of PI. 
alpina. 
a.h.i. 
Anterior branch of in¬ 
p.b.i. 
Posterior branch of in¬ 
testine. 
testine. 
at. 
Atrium. 
ph. 
Pharynx or proboscis. 
au.o. 
Auricular organ. 
ph.s. 
Pharyngeal sheath. 
e. 
Eye. 
s. 
Sucker. 
g-P- 
Genital pore. 
t. 
Tentacle. 
1 . 1 . 
Lateral lobe. 
t.c.b. 
Transverse commissure of 
m.g.o. 
Musculo-glandular organ. 
brain. 
mo. 
Mouth. 
ut. 
Uterus. 
P. 
Penis. 
ut.d. 
Uterine duct. 
