DEPARTMENT OF MARINE BIOLOGY. 181 



the original intention was to avoid making a cross between the local and the 

 introduced forms. 



On Garden Key, Tortugas, we found only a single specimen of the cerions 

 planted. No trace of the second planting within the fort was found. The 

 burning to which they were subjected last year seems to have exterminated 

 them, so that the Garden Key colony, as a whole, is practically a failure. 



On the other hand, on Loggerhead Key most of the colonies are doing 

 very well, but nowhere did we find an adult specimen of the second generation. 

 Judging from the large number of young individuals, there is no doubt that 

 the coming year will yield a great number of this most interesting generation. 



Condition of Colonies on Loggerhead Key, Tortugas. 



Colony A. Young and adults were everywhere in evidence at this colony, 

 which seems to be in an extremely flourishing condition. We left the snails 

 undisturbed. 



Colony B. This consisted of a planting of 500 tips of first-generation 

 Florida-grown "White House" type cerions. We gathered 73 adults and 4 

 half-grown individuals. Last year we took from this same colony 139 

 specimens which, after measuring, we replanted as Colony J. This shows 

 that at least 202 of the 500 tips reached or almost reached maturity. Measure- 

 ments and photographs were taken of this year's specimens. They were 

 placed with the remnant of Colony C. 



Colony C. Very few shells were apparent in this colony, and since there is 

 a possibility that there might be young individuals buried in the sand, we 

 did not deem it wise to disturb the ground by walking over it and making 

 a careful search for shells, since under no circumstances could adults of the 

 second generation have appeared. In addition to the snails added from 

 Colony B, we also placed here the 7 living specimens remaining of Colony J. 



Colony D. Two dead shells only were observed. The painted cerions 

 appear not to be well suited to this condition. 



Colony E. This colony resembles Colony A hi spreading over a Avide area, 

 and many young, and also adult shells, could be seen everywhere. 



Colony F. This colony, which was planted in 1914, is doing remarkably 

 well. We gathered 300 tips of the first generation, which I have replanted 

 as Colony M. Of the originally planted shells, 178 were easily found, and 

 these we placed again near the stake. 



Colony G. We gathered 78 adults of the first generation of Florida-grown 

 specimens of this colony, which were photographed and measured and 

 returned to the stake marking this colony. 



Colony H. This colony has again been subjected to a burning and I doubt 

 if any cerions have escaped. 



Colony L This mixed colony, which is a replanting of the original material 

 planted at Colony H, seems to be doing fairly well at its new location. We 

 easily recovered 83 specimens of the originally planted "Kings Road" type, 

 of which 28 were dead, and 115 specimens of the originally planted "White 

 House" type, of which 27 were dead. We also found 18 young, probably 

 belonging to the "White House" type. All of these we placed near the stake. 



Colony J. Here we placed 139 specimens of the first generation of Florida- 

 grown "White House" type cerions taken from Colony B last year. Of 

 these we recovered 121 this year, all but 7 of which were dead. The 7 living 

 specimens we have combined with Colony C. 



Colony K. This colony appears to be in thriving condition. 



Colony L. This colony, consisting of the 800 Porto Rico cerions planted 

 last year, is doing well. We made no attempt to gather the snails. 



