494 . EDWIN S. GOODRICH. 



10. Oka, a. — " Beit.rage zur Anatomie der Clepsine," ' Zeit. f. wiss. Zool.,' 



vol. Iviii, 1894. 



11. Sedgwick, A. — ' Student's Text-book of Zoology,' vol. i, London, 1898. 



12. Shipley, A. E. — " On the Existence of Communications betvpeen the 



Body Cavity and Vascular System," ' Proc. Cambridge Phil. Soc.,' 

 vol. vi, 1888. 



EXPLANATION OF PLATES 42—44, 



Illustrating Mr, Edwin S. Goodrich's paper " On the Com- 

 munication between the Coelom and the Vascular System 

 in the Leech, Hirudo medicinalis.^' 



All the figures are of Hirudo medicinalis. The contractile vessels and 

 Itieir branches are coloured pink, the sinuses and their branches are coloured 

 blue. 



EiGs. 1, 2, AND 3. — Reconstructions, from a series of 600 sections, of the 

 main trunks of the contractile and sinus systems. Figure 1 shows a dorsal 

 view of the lateral vessels and dorsal sinus. Figure 2 shows a left-side view 

 of the lateral vessels, dorsal sinus (without its branches), ventral sinus, and 

 periuephrostomial sinus. Figure 3 shows a more complete view from above 

 of the ventral sinus and its branches, with tlie nerve-cord visible by trans- 

 parency, the lateral vessels with their latero-abdominal branches. 



Fig. 4. — Beconstruction as seen in transverse section of sections 50 — 150, 

 front view. A capillary, C, is seen to join the right latero-abdominal vessel 

 with the abdomino-dorsal sinus. 



Fig. 5. — Reconstruction as seen in transverse section of sections 213 — 360, 

 front view. The position of the gonads is indicated by a dotted line. 



Fig. 6. — Portion of section 340 partially reconstructed backwards, showing 

 the connection, at C, between a small sinus and a branch of the latero-dorsal 

 vessel. Dotted lines indicate the general course of the latero-dorsal vessel, 

 which is several times cut through. 



Fig. 7.— Reconstruction showing the communication between a branch of 

 the latero-dorsal vessel, and a branch of the dorsal sinus ; also capillaries 

 opening from the intermediate plexus into the botryoidal tissue. From another 

 series. 



Figs. 8, 9, 10, and 11. — Camera drawings of three consecutive sections, 

 and a reconstruction of tlie same, showing tlie continuity between the two 



