PLATE LI. 



[Part y.—June 1884.] 



Fig. 1. Cyclophorus aukora, Bs., j; , x 2-4. Animal from spirit-specimen. Damsang 

 Peak, W. Bhutan Hills, m, the mantle drawn back, showing {a.o) the anal 

 orifice and p the penis ; ?-, the rostrum ; /, sole of foot folded together ; s.m, 

 shell-muscle ; o, operculum . 



2. Cyclophorus aurora, Bs., ? , x 2'4. Spirit-specimeu. Animal withdrawn into 



the shell. Viewed from the outer side of the aperture. Greater portion of shell 



broken away, showing foot folded together. Same locality. 

 2 a. Ditto : ditto, x 2--i. Viewed from the right side. 

 2 b. Ditto : ditto, x I'G. Viewed from the left side, showing form of the mantle and the 



branchial cavity (b.c). 

 2c. Ditto: ditto, x 1-6. Viewed from the right side, to show the shell-muscle {s.m). 

 2 (L Ditto : ditto, x 1'6. The mantle cut and opened back to show the anal orifice 



and interior of the branchial cavity. 



3. Alyc.eus nagaensis, G.-A., enlarged. Animal from spirit-specimen. 

 4. BiCRENATUs, G.-A. One row of the radula. Much enlarged. 



5. BEMBEX, Bs. Sutural tube {t) of the whorl of the shell broken away, to show 



the internal orifice of the same (o./). 



6. Alyc/eus NAGAENSIS, G.-A., X 7. The outer right margin of the shell broken away, 



to show the sutural tube {() iu the internal orifice of the same (o./). 

 6 a. Diagrammatic section of the frontal edge of the mantle {m) in Alyc^us, by which the 

 sutural tube is formed. 



7. Raphaulus blanfordi, Bs., enlarged. Animal removed from shell, showing the 



sutural or branchial tube (t) . 



8. Ditto, X 7. Shell with margin broken away, to show the internal orifice [o.t] of 



the sutural tube (t), extending forward to the peristome. 



9. Raphaulus blanfordi, Bs., X 20. A portion of the shell near suture, to show the 



internal sutural tube [t] and the external sutural tube (/'), corresponding to that 

 iu fig. 7. 

 •J u. Diagrammatic section of the same across the front edge of the mantle (wt), to illustrate 

 the formation of the iutcrnal and external sutural tubes {t, /')• 



