DEPARTMENT OF MARINE BIOLOGY. 171 



not have been done. A single young specimen was also discovered, slio\\ang 

 that they have been breeding here. We transplanted the whole lot to the 

 inside of the fort, pretty well in the center, where the conditions appear 

 to be much more favorable than at the last place, and now that the fort is 

 about to be abandoned little fear of interference with this colony need be 

 expected. The place where the planting was made is nearest the house, 

 just after leaving the trees on the main path from the entrance to the house; 

 on the left side of the path we marked the place with a stake; GO of the 62 

 found were alive; the two dead specimens had been crushed by something 

 which had evidently preyed upon them. 



Only 8, and no young, of the 72 small painted cerions planted on Bird 

 Key were found, and it is more than probable that this little colony will not 

 be successful. 



On Loggerhead Key three plantings were made which may be referred 

 to as the northern, the middle, and the southern. The northern consisted 

 of 500 of the "White House," type; the middle consisted of a mixture of 

 500 each of the "White House" and "King's Road" type, while the southern 

 was composed of 500 of the "King's Road" type. The northern planting 

 is largely in a cactus patch (Plato punt ia), and it was necessary to uproot 

 a lot of these plants in order to hunt for the shells. The animals were doing 

 well and 82 young were secured without much difficulty; 7 of the largest 

 of these were taken to Washington for comparison with the check series, 

 vnth which they agree in every particular; the largest specimen has seven 

 post-nuclear whorls. The southern planting is situated in a sandy plain, 

 covered with a stiff grass, and this seems to be an ideal condition for these 

 organisms. Here I gathered 55 young in 20 minutes in a space of 3 square 

 yards. The young were all about the base of the tussocks of grass, and 

 some on the ground. I did not disturb the planted material. In all I 

 secured 82, of Avhich 7 were taken to AVashington; these are all small, the 

 largest having a little more than four post-nuclear whorls, but they agree 

 in every way with the check series. This is by far the most flourishing of 

 all the colonies. The middle colony is in a dense cactus patch, mixed with 

 rank grass and some brush. An hour's hunting revealed no young speci- 

 mens, and from the experience obtained at the southern planting, where 

 many of the young are near the ground or on it, it was deemed best not to 

 disturb this planting at the present time, but to wait until next year, when 

 the young will have attained a larger size, or probably maturity, before 

 making an exhaustive study of this colony. At the light-house dock on 

 the west side I noticed that several dead shells of the cerions planted were 

 occupied by hermit crabs, and although conditions like this were not 

 observed in any of the other colonies, it seems possible that some of the 

 shells may have been carried away in this manner. 



On April 13 plantings of the young of the two races of cerions produced 

 on Loggerhead Key were made in cages near the laboratory ; 50 of each tj^pe 

 were put in a fine-wire-screened cage in which suitable plants had been 

 placed, while in a third cage 25 of each were placed, thus giving these a 

 chance to cross if they will do so when they attain maturity. 



The results so far obtained seem to indicate that the first generation will 

 be like the parent generation unless decided changes should take place in 

 the later whorls, which have as yet not been developed. The largest speci- 

 mens found so far have only seven post-nuclear whorls, leaving two to three 

 whorls still to be developed, and these make up fully half of the length of 

 the shell. If the present tendencies prevail in the adult shell, then we can 

 see that the somaplasm has not at once responded to the change of environ- 



