DEPARTMENT OF MARINE BIOLOGY. I29 



Alfred G. Mayer, The Carnegie Institution. Ctenophores of the Atlantic coast of 

 North America. Publication No. 162 of the Carnegie Institution of Wash- 

 ington, 58 pp., 17 plates, 12 text-figures, March 1912. 



Edith Pinney, Bryn Mawr College. A study of the chromosomes of Hipponoe 

 esculenta and Moira atropos. Biological Bulletin, Woods Hole, vol. 21, pp. 

 168-186, 31 figs., August 191 1. 



H. S. Pratt, Haverford College. On Galactosomum cochleariforme Rudolphi. 

 Zool. Anzeiger, Bd. 38, pp. 143-148, 5 figs., August 191 1. 



D. H. Tennent, Bryn Mawr College. A heterochromosome of male origin in 

 echinoids. Biological Bulletin, Woods Hole, vol. 21, pp. 152-154, 3 figs., 

 August 1911. 



Sixteen investigators are now prepared to present the results of their 

 studies, and it is expected that these papers will provide manuscript for at 

 least two more volumes of the series of "Researches from the Tortugas 

 Laboratory," of which volumes i to 4 have already been published by the 

 Carnegie Institution of Washington. 



In conclusion, it is a pleasure to speak of our appreciation of the kindness 

 of the late Admiral Young, U. S. N., who as Commandant of Key West, did 

 much to aid us in our studies. 



REPORTS OF INVESTIGATORS. 



Planting Bahama Cerions upon the Florida Keys, by Paul Bartsch, 



U. S. National Museum. 



At the invitation of Doctor Mayer I joined the expedition of the Anton 

 Dohrn to the Bahama Islands, the main object of my visit being an ecological 

 study of the marine mollusks of the region, with special reference to the 

 boring and nestling organisms associated with corals. Collections were made 

 wherever possible, but most of the work was done in the region of the east 

 end of South Bight, Andros Island. The marine mollusks proved rather dis- 

 appointing, there being but few species, and these, with few exceptions, were 

 poorly represented in numbers. A detailed report of the findings will be 

 made in the near future. The land shells of the region proved far more 

 interesting than the marine mollusks, and among these the genus Cerion 

 presents some most interesting problems. 



Andros Island is a collective term applied to a whole host of minor keys, 

 separated by tortuous channels of varying width and depth. Practically each 

 key examined, no matter how small, provided it bears vegetation, excepting 

 those in the Tongue of the Ocean, which are at times dashed over by ocean 

 waves, is inhabited by Cerions of the glans group. Sufficient differentiation 

 has taken place on each key to enable one to distinguish the shells from the 

 different keys. For example, in size alone, 500 of those collected about Bas- 

 tion Point (see map, plate 3) filled a 3-pint measure, while the same number 

 from the neighborhood of our temporary laboratory (the "White House," 

 near Sharp Rock Point) required a 5-pint measure to contain them. There 

 are also other characteristics correlated with size. 



On the northwest side of Linder Key, along Lisbon Creek, a series of 

 swales separate an equal number of wooded elevations only a few feet above 

 high-water mark. We found that these swales separate different races of 

 Cerions. What has been said of the glans group also holds good of the 

 painted Cerions wherever they occur, although their distribution seems to be 

 more restricted. In the light of all these puzzling facts, it was deemed de- 



