302 DR J. STEPHENSON ON 
REFERENCES TO LITERATURE. 
(1) Asuworru, J. H., “The Giant Nerve Cells and Fibres of Halla parthenopeia,” Phil. Trans. Roy. Soc. 
Lond., series B, vol. ec. (1909), 
(2) Bepparp, F. E., “A new branchiate Oligochete (Branchiura sowerbyt),” Quart. Journ. Mier. Science, 
N.S., vol. xxxiii. (1892). 
(3) Bepparp, F, E., A Monograph of the order Oligocheta, Oxford, 1895. 
(4) Bournn, A. G., “On Chextobranchus, a new genus of Oligochetous Chetopoda,” Quart. Journ. Mier, 
Science, N.S., vol. xxxi. (1890). 
(5) Micwartsen, W., ‘ Oligocheta,” in Das Tierreich, Berlin, 1900. 
(6) Micuartsen, W., “Zur Kenntnis der Tubificiden,” Arch. fiir Naturgesch., vol. Ixxiv., Bd. i., Heft 1, 
Berlin, 1908. 
(7) Micuagtsen, W., ‘‘ Die Oligochatenfauna der orhontachvsmeace lena an Region,” Abh. aus dem Cebiete 
der Naturw. hgbn. vom Naturw. Verein in Hamburg, Bd, xix., Heft 5 (1910). 
(8) Perrier, Lton, “Une station rhodanienne de Branchiura sowerbyi Bedd.,” Ann. de Puniversité de 
Grenoble, tome xxi., no. 1., Paris, 1909. 
(9) SrepHenson, J., “Studies on the aquatic Oligocheta of the Punjab, I.,” Records of the Indian Museum, 
vol. v., part i. (1910). 
(10) SrepHensoy, J., “On some littoral Oligocheta of the Clyde,” Trans. Roy. Soc. Edin., vol. xlviii., pt. i, 
(1911). 
(11) Vespovsky, F., System und Morphologie der Oligocheten, Prag, 1884. 
EXPLANATION OF FIGURES. 
(Figs. 2, 3, 4, 5, 6, 10, 11, 16 drawn by camera lucida.) 
Fig. 1. Single- and double-pointed sete of Branchiura sowerbyi. x 450. 
Fig. 2. Section through anterior part of Branchiura sowerbyi; septum 4, which is bulged backwards, 
is cut through in the upper part of the figure. Blood-vessels shaded. x 154. 
circ, m., circular muscular coat ; ep., surface epithelium ; in. circ, m., inner circular muscular coat; 1. 1, 
lateral line cells; dong. m., longitudinal muscular coat ; m. set., dorso-ventral muscular bundle between setal 
sacs of same side; @s., esophagus; p., peritoneal cells (“septal gland”’); s., ventral seta of segment iv; 
sept., septum + Ras of decussating muscular fibres ; v. 7. c., ventral nerve cord, with giant fibre dorsally. 
Fig. 3. Section through gill region of the same ; re enanor face of the section is towards the observer, 
z.e. left and right are reversed. The longitudinal agentlar layer is here broken up, leaving visible a fibrille 
groundwork with a few nuclei. x 250. 
c., a group of cells connected with the ventral vessel, prominent in this particular section ; chl., ehlora : 
gogen cells; d. v., dorsal vessel, showing a connection with the enteric plexus; g. f., giant fibre, ta the left 
of which, in the figure, are seen a row of similar but smaller fibres; 7nt., intestine ; plew., part of intestinal 
blood-plexus ; v. v., ventral vessel. Other references as above. 
Fig. 4. Cells of the lateral line in the posterior part of the same, in transverse section. The lateral 
line is here discontinuous ; where present the cells project some distance inwards and spread out. x 560. 
cut., cuticle ; int. ep., intestinal epithelium ; iné. m., intestinal muscular coat ; per., peritoneal cells round 
intestine. Other references as above. 
partition, the absence of a definite body-cavity in the ventral part of the section, and the relatively large s 
of the ventral nerve cord. «x 250. 
m., bands of muscle fibres, in various directions; transv., transverse band (the coelomic partition) ; &y 
groundwork of fibrille and nuclei. Other references as before. 
