224 



Ohs. — The fry reveal a spiral nucleus of two full turns, 

 dextral, smooth, and horn-coloured. In some, especially the 

 smaller, the ribs are more distinct and the sculpture less rug- 

 ged. Some have much more brown colouring, either in the 

 intercostal spaces or in the internal horseshoe or both. One 

 has the enlarged extremities of the horseshoe muscle-scar 

 plainly painted. We have no other Siphonaria with its apex 

 so near the posterior end. The largest example is 9*4 mm. 

 by 6'5. I have named the species after Miss Stow, who col- 

 lected the immature examT^les. 



EXPLANATION OF PLATES. 

 Plate VTIT. 



Fig. 1. ScufeUina alhoradiata, Verco. — Ventral view. 

 ,,2. ,, ,, ,, Side view. 



,, 3. Si2:)}ionarui stowa',, Veroo. — Dorsal view. 

 ,, 4. ,, ,, ,, Ventral view. 



,, 5. ,, ,, ,, Side view. 



,,6 ,, ,, ,, Radiila. 



,, 7. ,, ,, ,, Radnla. rachidian, and 



first lateral from the 

 other half. 

 ,,8. ,, ,, ,, Fifth lateral, side view. 



,, 9. Scutellina calva, Verco. — Ventral view ! 

 ,,10. ,, ,, ,, Side view ! 



,, 11. Nacella compressa, Verco. — Side view. 

 ,, 12. ,, ,, ,, Ventral view. 



Plate IX. 



Fig. 1. T/ipplsfcs vieridionalis, Verco. 

 ,,2. ,, ,, ,, Protoconch. 



,, 3. Segvenzia poUfa, Verco. 

 ,,4. ,, ,, ,, Lip in profile 



,, o. ,, ,. ,, Basal view. 



,, 6. lAppUtcp; separatista, Dillwyii. — Spire, full view. 

 ;, ,, ,, With epidermis. 



,, ,, Operculum. 



,, ,, ,, Radnla. 



Plate X. 



Basil'is'^n radialis, Tate, var. h'lli.r, Hedley. 



,, ., ., Base. 



,, ,, ,, ,, Outer lip. 



Narrlla stoira', Verco. — Ventral view. 



,, ,, Side view. 



HeJcloiiiscus illihrafd, Verco.- -Side view. 



,, ,, ,, Ventral view. 



,, ,, ,, Radnla, front view. 



,, ,, ,, Laterals, side view. 



,, ,, ,, Marginal, side view. 



,, A second radnla, front 



view. 

 ,, ,, ,, Laterals, side view. 



A third radnla, front 

 view. 

 14. ,, ,, ,, A lateral, vside view. 



