636 NOTES ON PROSOBRANCHIATA. 



Fig. 4. — Genitalia ( $ ). — ovij)., ovipositor (?). ut., uterus, ovid., oviduct, 

 jiej:*/^ , nephridium. gl., ovary, r.j^.o., reno-pericardial orifice. 



Fig. 5. — Ctenidium. — b., venous lacuna, nejyh.v., nephridial vein, vent., 

 ventricle. rt?rr., auricle, fe?'.!?. , branchial vein. 



Fig. 6. — Anterior portion of the digestive tract. — buc, buccal mass, sal.gl.y 

 left salivary gland, app., left appendage, ant.ces., anterior 

 oesophagus. crop, crop, post.aes,, posterior oesophagus. I., 

 lumen, rad., radula. 



Fig. 7. — Rachidian tooth. 



Fig. 8. — Penis showing sphincter muscles, and seminal canal squeezed out 

 between lines of contraction. 



Fig. 9. — One lobule of ovary showing ovules arranged round the edge. 



Fig. 10.— Crop. — I., lumen. 



Fig. 11. — Young shell. 



Fig. 12. — Nervous system dissected out and drawn with the camera lucida 

 as seen floating in water. — e.g.', left cerebral ganglion, e.g.", 

 right cerebral ganglion. pl.g.\ left pleural ganglion, pl.g.", 

 right pleural ganglion, pd.g. ', pd.g." , left and right pedal ganglia, 

 sb.int.g., subintestinal ganglion. sp.int.g., supra-intestinal 

 ganglion, sp.int.con., supra-intestinal connective, sb.int.con., 

 subintestinal connective, c. 2)1. con., cerebropleural connectives. 

 c.pd.con., cerebro-pedal connectives, pl.pd.con., pleuropedal 

 connectives, dial. con., dialoneurous connection (?) c.b.con., 

 cerebro-buccal connectives (?) n.gen., genitalia nerve (?) nv.\ 

 n.v." , left and right visceral nerves, n.pal.', n.pal." , left and 

 right pallial nerves, n.col., columellar nerve (?) p.g.k., ganglionic 

 knots. 



Fig. 13. — Nervous system seen from above. Lettering as in fig. 12. 



