DEPARTMENT OF MARINE BIOLOGY. 189 



even though the medusa may then pulsate at fully twice its normal 

 rate by means of an entrapped stimulus. This is interesting in con- 

 nection with Dr. L. R. Gary's discovery that if the sense-organs be 

 intact the initial stages of regeneration are more rapid than if they 

 be removed, and even a single sense-organ is competent to maintain 

 this adjustment. There thus appears to be a profound control exer- 

 cised by the central nervous system over metabolism and regeneration. 



Other details of Dr. Gary's studies will appear in his preliminary 

 report herewith presented, but it would be well to mention that he 

 finds the alcyonaria to be an even more important factor in forming reef 

 limestone than he had previously supposed. 



Professors Alexander H. Phillips and Gilbert van Ingen made an 

 extensive collection of marine invertebrates, which they dried and 

 prepared, to enable them to determine what heavy metals, such as iron, 

 copper, etc., these animals may contain. They also collected samples 

 of the sulphureted mud from the mangrove swamps for a similar pur- 

 pose. It is believed that certain deposits of iron and copper owe their 

 origin to marine mollusca, worms, etc., and the subject should therefore 

 be studied with existing animals. Several months must elapse before 

 these investigators can present a report of their results. 



Dr. Paul Bartsch again visited his plantations of cerions from Andros 

 Island, which have been placed upon various Florida keys from the neigh- 

 borhood of Miami to the Tortugas. He finds that the Florida-born young 

 differ from their Bahama-born parents. The meaning of this can not be 

 ascertained until several generations of Florida-born young have been 

 produced, and until some of these have been returned to their ancestral 

 locality on Andros Island and there observed. An intensive study of 

 the habits, anatomy, possible differential death-rate, and embryology of 

 these snails must also be made before conclusions can be estabUshed. 



Professor Eugene W. Gudger continued his study of the anatomy of 

 sharks, spending about two weeks at Key West before going to Tortu- 

 gas for this purpose. 



Professor Edwin E. Reinke continued his study of the physiological 

 reactions of the two kinds of sperm-cells in Strombus, testing for the 

 effects of GO2 in sea-water under various conditions. These cells are 

 exceedingly sensitive and somewhat variable in their responses, thus 

 rendering this research so difficult that only an investigator of the 

 highest determination, patience, and ingenuity could hope for success 

 in its prosecution. 



A. G. Mayer continued his studies of the rate of nerve conduction in 

 Cassiopea in diluted and in concentrated sea-water, using for dilution 

 distilled water freed fromG02 and rendered slightly alkahne by N/10000 

 NaOH. Mayer's theory of nerve conduction is that sodium, calcium, 

 and potassium cations of the sea-water are attracted by adsorption 

 to the surfaces of negatively-charged colloidal elements of the nerves. 



