Plate XVIII. 



Fig. 1—4. Conulema attegia, Benson, p. 237. 



I, genital organs; 1$, section of the amatorial gland; 2, diagram^ 

 matic view of the mantle lobes; 3, jaw; 4, different teeth of one 

 transverse series. 



Figs. 5 — 9. Conulema infula, Benson, p. 239. 



5, side view of an animal, from Calcutta; 6, genital organs 

 during the winter season ; 7, anterior portion of the same during 

 the rainy season; 8, jaw; 9 various teeth of one transverse series. 



Fig. 10, Conulema liricincta, Stol., p. 241. 



Figs. 11 — 13. Microcystis molecula, Benson, p. 251. 



II, genital organs; 12, jaw ; 13, a few teeth from a transverse 



series. 



ag, amatorial gland j ho, hermaphrodite opening 5 to, retractor muscle j 

 p, penis ; ps, calciferous sac 5 vd, vas deferens 5 %>r, prostata ; ut, uterus ; hd, her- 

 mapbi-odite duct; lig, heramph. gland j alg, abbuminous gland; rs, receptacu- 

 lum seminis ; ov, enlarged ovary sac 5 rsl, right shell lobe of the mantle ; rsl f , 

 lower end of the same j Isl, left shell lobe ; lsl\ lower end of the same ; rdl, 

 right dorsal lobe ; Idl, left dorsal lobe ; «, @, y t 8, successive layers in the 

 section of the amatorial gland, (fig. la). 



