4 EXPERIMENTS IN THE BREEDING OF CERIONS. 



Report on the Bahama Cerions planted on the Florida Keys, Carnegie Inst. Wash. Pub. 



No. 212, 1915, pp. 203-212, plates 1-8. 

 Report on Bahama Cerions planted on the Florida Keys, Year Book No. 14 of the Carnegie 



Institution of Washington, 1915, pp. 194-196. 

 Report on the Bahama Cerions planted on the Florida Keys, Annual Report of the Director 



of Department of Marine Biology, Carnegie Institution of Washington, extract 



from Year Book No. 15 for the year 1916, pp. 179-182. 

 Visit to the Cerion Colonies in Florida, Smithsonian Miscellaneous Collections, vol. 66, No. 



17, 1917, pp. 41-44. 

 A Visit to the Cerion Colonies in Florida, Smithsonian Miscellaneous Collections, vol. 68, 



No. 12, June, 1918, pp. 48-49. 



The Florida Keys were considered to be a favorable region into which 

 these Bahama forms might be introduced, for these keys stretch for 

 more than 240 miles from Virginia Key on the north to the Dry Tor- 

 tugas in the Gulf of Mexico, and present quite a range in climatic 

 factors and vegetation. Many of them harbor an indigenous species, 

 Cerion incanum (Binney), which, however, is quite unrelated to those 

 that have been introduced. Furthermore, in selecting sites for our 

 colonies we aimed to avoid placing the introduced forms where the 

 native species existed. Colonies of 500 each w r ere planted on the keys 

 in 1912, as will be seen in the following pages. The shells of the mol- 

 lusks planted were marked by two parallel file cuts made across two 

 or more ribs. This method of marking has proved very satisfactory. 



Two Bahama species were planted in the first introduction. These 

 are what are now termed Cerion casablancce, a new species gathered in 

 the neighborhood of the White House, which was our laboratory during 

 the 1912 cruise, and which is situated between Sharp Rock Point and 

 Driggs Hill, on the southeast side of South Bight, Andros Island. This 

 species has been referred to in the previous reports as the White House 

 type of Cerion. The material of the other species, which I am calling 

 Cerion viaregis in the present paper, was gathered along King's Road, 

 Bastion Point, on the northeast side of South Bight, Andros. The 

 mollusks from this region have been referred to in the past reports as 

 the King's Road type of Cerions. In addition to these two, 73 speci- 

 mens of a small mottled Cerion (species ?) from Andros were planted 

 on Bird Key. These have since disappeared without leaving any 

 trace of progeny. They will therefore not be referred to again. 



An additional importation of 500 specimens of Cerion viarevis 

 gathered in 1914 was planted on Loggerhead Key (Colony F) on June 

 9 of the same year. On the same date a second colony of mottled 

 Cerions, Cerion (species ?), gathered at Spring Hill, Nassau, by Dr. 

 Mayor in 1914, was made on Loggerhead Key. This colony has also 

 disappeared, a few dead shells only remaining, so it also may be dis- 

 regarded in our discussion. Our unfortunate experience with the 

 painted Cerions in the Tortugas may indicate that this group does 

 not find the environmental conditions suitable for its maintenance. 



