DEPARTMENT OF MARINE BIOLOGY. 169 



SPECIAL REPORTS OF INVESTIGATORS. 



Report of Results of the Planting of Bahama Cerions on the Florida Keys, 

 by Paul Bartsch. 



In the annual report of the Director of the Department of Marine Biology 

 of the Carnegie Institution for 1912 (Year Book No. 11, pp. 129-131) 

 attention was called to the transplanting of a large number of two races of 

 Bahama cerions to Florida Keys, We visited these plantations this spring 

 and noted the following results : 



On April 25 we visited the plantation on the second Ragged Key north of 

 Sands Key, where 500 cerions of the ''King's Road" type were planted. 

 We recovered 260 of the planted specimens, all living, and two shells which 

 had been partly broken by some animal in order to extract the flesh. These 

 moUusks Avere found in the grass, on low bushes, and on the dead drift 

 shrubbery. It is possible that the greater part of the planting might have 

 been recovered if sufficient time had been devoted to it, as additional speci- 

 mens were discovered every time we went over the ground where the planting 

 was made. There was no need for doing this, however, since the collected 

 material showed that the colony was in good condition. 



The most interesting part of the visit to this colony was the finding of 

 11 young cerions which were born on this key; they were attached to a 

 grass (Gayoides imberhe); of these, 3 were of similar size and much larger 

 than the rest, which consisted of a little more than the nepionic whorls. 

 Two of the larger young we took to Washington. These have 3.1 and 3.4 

 post-nuclear whorls, and agree in every way with the check series from the 

 Bahamas. The rest we painted with black asphalt paint and left them in 

 the originally planted colony. 



The next visit was to the first Ragged Key north of Sands Key, where 

 500 cerions of the "White House" type were planted. Here most of the 

 mollusks were attached to the stems and leaves of a densely matting, succu- 

 lent plant {Sesuviwn -portulacasirum). The shells were hard to see, having 

 the same color as the coarse coralline sand, and the fact that they were 

 kept close to this bj^ the trailing food-plant made it difficult to find them. 

 Dead stumps, twigs, and bushes also formed a favorite habitat and in such 

 locations the shells were usually found in clusters. On this key 220 of the 

 planted specimens were recovered, all of them alive. Here we also found 

 three young shells produced on the island, which were retained for closer 

 laboratory study and comparison with the check series. These three shells 

 have 1^, 1|, and 2 post-nuclear whorls, respectively, and agree in every 

 way wdth the check series from the Bahamas. 



On April 26 we visited the planting of 500 cerions of the "White House" 

 tj'pe on Indian Key. Here they had been quite active, some having moved 

 as much as 60 feet from the place where they had been planted. We 

 recovered 245 in about an hour, and these were mostly on dead sticks and 

 usually clustered, though a good many were found on Sesuvium. The vege- 

 tation has grown up so rank at this place that it now seems ill-suited for 

 these organisms, and this may have been responsible for the great mortality 

 among them, for we found 20 of the 245 dead — not a single young individual 

 was observed. This, however, does not necessarily mean that none existed, 

 for young cerions are exceedingly hard to find. We shifted the gathered 

 specimens to the center of the island, which was drier and less densely 

 covered with vegetation. The 225 living specimens were planted near the 

 southern part of the west wall of the two foundation walls north of the 



