464 W. A. HASWELL. 
20. Marx, E. L.—“Polycherus caudatus, nov. gen., nov. sp.,” 
‘Festschr. R. Leuckarts.’ 
21, PEREYASLAWZEWA, S.— Sur le développement des Turbellariés,” ‘ Zool. 
Anz.,’ 8 Jahrg. (1885). 
22. PernyasLawzEwa, S.—‘‘ Monographie des Turbellariés de la Mer Noire” 
(1892). 
23. Repracnorr, W.—“< Nachtrag zu vorstehender Mittheilung ” (21), ‘Zool. 
Anz.,’ 8 Jahrg. (1885). 
24, Sasussow, H.—“‘ Haplodiscus Ussowli, eine neue Acéle aus dem 
Golfe von Neapel,” ‘ Mitth. Z. Stat. Neapel,’ Bd. xii. 
25. Scumipt, O.—‘‘ Neue Rhabdoceelen 8. B. der mathemnaturw. Klasse der 
Kais,” ‘ Akad. der Wiss.,’ Bd. ix. 
26. Scuneiper, K. C.—‘‘Lehrbuch der vergleichenden Histologie der 
Thiere ” (1902). 
27. Scuutrze, M. S.— Beitrage zur Naturgeschichte der Turbellarien” 
(1851). 
28. Vespovsky, F.—‘‘ Zur vergleichenden Anatomie der Turbellarien,” 
‘ Zeitschr. wiss. Zool.,’ Bd. Ix. 
EXPLANATION OF PLATES 25—27,} 
Illustrating Prof. W. A. Haswell’s paper, “ Studies on the 
Turbellaria.” 
List oF REFERENCE LETTERS. 
a. Atrium. anf. Antrum femininum. 4. Bursa copulatrix. 4/7. Bulb of 
bursa seminalis. 4.m. Basement membrane. Gr. Brain. &.s. Bursa semi- 
nalis. &.s!. Outer layer of wall of bursa seminalis. 0. s®. Inner layer of wall 
of bursa seminalis. 6.s.d. Duct leading from antrum to bursa seminalis. 
c. So-called cuticle. ch. Chitinous mouth-piece. ch. c. Cells secreting sub- 
stance of chitinous mouth-pieces. c. m. Layer of circular muscular fibres of 
body-wall. cp. Capillary canals in epidermis. c¢.w. Cell-wall of Alga. 
1 Figures 7, 9, 10, 12, 13, 16, 21, 22, 26, 28, and 32 were drawn by Mr. 
A. Cronin, of the Physiological Department of Sydney University, from my 
photographs of sections, of which they are, to all intents and purposes, fac- 
similes. 
