OP COCHLITOMA ZEBRA IN CONFINEMENT, 387 



times the mollusc would remain buried while merely the head was 

 protruded for feeding. 



I am greatly indebted to Mr. G. 0. Robson for several valuable 

 suggestions, also for affording me every facility when studying 

 specimens under his care. 



EXPLANATION OP THE PLATES. 

 Plate I. 

 Cochlitoma zebra, var. obesa (Pfeifter). 



Fi- 1. Brood I. Drawn June 17th, 1914. X 2. Born April 29th, 1914. 



2. Brood II. Drawn shortly after birth, May 4th, 1914. X 2. (Shell lost.) 

 2a. Brood II. Sculpture, greatl}' enlarged. 



3. Brood II. Different specimen, drawn June 17th, 1914. X 2. 



4,4a. Brood II. Eggs of medium and small size. X 2. Larger one showing 

 inner amber-like layer. 



CocMitoma zebra, vawfalgurata (Pfeiffer). 



5. Drawn May 4th, 1914, soon after birth. X 2. (Died after visit to the 



Museum.) 

 o a. Sculpture greatlv enlarged. 



6. Drawn June 17tli, 1914. X 2. Hatched from an egg. May loth or 17th, 1914. 



7. Egg, laid May 7lh, 1914, showing inner amber-like layer. X 2. 



8. Embryo, with egg-shell partly broken away, and showing inner thin cal- 



careous layer, also the brown markings on the last whorl. X 2. 



9. Specimen previously figured June 17th (fig. 6), drawn again July 28th, 



1914. X 2. 



10. The same, drawn September loth, 1914. X 2. (Died immediately after- 



v/ards.) 



11. Another shell, drawn April 9th, 1915. X 2. 



12. The same, drawn June 30th, 1916. Nat. size. (Died June 1917.) 



13. Portion of epiphragm, showine: slit. X 2. 



Plate II. 



Cnclilitoma zebra, var. obesa (Pfeiffer). 



Fig. 1. Brood I. Same as PI. I. fig. 1, drawn July 28th, 1914. X 2. 



2. „ ., „ „ September loth, 1914. X 2. 



3. „ „ „ „ April 9th, 1915. X 2. 



4. „ „ „ „ June 30th, 1916. Nat. size. (Died 



September 1916.) 



5. Brood II. Same as PI. I. fig. 3, drawn July 28th, 1914. X 2. 



6. „ „ „ „ September loth, 1914. X 2. 



7. ., ., „ ., April 9th, 1915. X 2. 



8. ', '„ ., „ June 30th, 1916. Nat. size. (Died 



February 1917.) 



Plate IIL 

 CoMitoma zebra, var. obesa (Pfeiffer). 



Fig. 1. Brood I. Drawn September 5th, 1917. Nat. size. (Not figured previously.) 

 Born April 29th, 1914. Died September 1920. Dissected by Mr. G. C. 

 Robson. 



Cochlitoma zebra, var. Jkilgurata (Pfeiffer). 



2. Drawn September 5th, 1917. Nat. size. (Not figured previously.) Hatched 

 from an egg, between May 15th and 2oth, 1914. Died September 1920. 

 Dissected by Mr. G. C. Robson. 



All the specimens figured have been given to the British Museum (Nat. Hist.). 



