158 CARNEGIE INSTITUTION OF WASHINGTON. 



Salvador. While a very large series and a good many new species of cerion 

 were discovered, the element in question was actually not obtained. At the 

 time of the present writing, Dr. Carlos de la Torre, President of the University 

 of Havana, who has brought his cerion collection to the U. S. National 

 Museum for comparison and study, has among them a strongly spirally 

 striated form from Cabanas, which is a little west of Havana. It will be 

 easy, therefore, to secure the desired material at that place. 



After two weeks' stay on San Salvador, the transport Kittery took Dr. 

 Bartsch from Cockburn Town to Guantanamo, Cuba, whence the journey to 

 Key West was by rail and boat. 



At Key West he was joined by Mr. Mills, the chief engineer of the Marine 

 Biological Laboratory. They proceeded to the Tortugas with the Velella, 

 stopping at the intermediate keys to examine the cerion plantations. 



At the Tortugas careful notes were taken on the various colonies, and two 

 new colonies were established : one of Porto Rican cerions in the southern part 

 of the island; one of the San Salvador cerions near the laboratory. On 

 the return trip the keys between Key West and Miami containing colonies were 

 examined and 150 living specimens from the hybrid colony on Newfound 

 Harbor Key were brought to Washington, where they have been carefully 

 treated for anatomic study, and it is intended to have 100 specimens of these 

 dissected in order to determine to what extent the internal anatomy is changed 

 through hybridization. So far as known, no reliable data are available on 

 this topic. 



As usual. Dr. Bartsch kept careful notes on all birds observed on the keys, 

 and he also took a series of under-water moving pictures among the coral reefs 

 of the Tortugas. 



Studies on Permeability with reference to Acids, Alkalies, Bicarhonates, and 



Arsenic, by Matilda M. Brooks. 



Mrs. M. M. Brooks carried out studies on permeability with reference to 

 acids, alkalies, bicarbonates, and arsenic. The marine alga Valonia, which 

 grows only in tropical waters, is specially adapted to such studies. It con- 

 sists of a single large cell with a central vacuole filled with sap. This sap can 

 be expressed and analyzed by direct chemical methods, thereby affording an 

 opportunity for direct observation of the permeability of the plant to sub- 

 stances of various kinds. In this way, many theories which have been 

 advanced in this respect can be definitely demonstrated to be either wrong or 

 correct. 



Field Investigations on the Variation, Distribution, and Evolution of Species of 

 the Genus Partula, by Henry E. Crampton. 



The months from May to September of 1923 were devoted to field-work 

 in Moorea, the island adjacent to Tahiti in the Society Group, and the 

 area on which the present researches are now focused. The previous 

 surveys of Moorea, made in 1907, 1909, and 1919, resulted in the discovery 

 of notable changes in the endemic species of the island since the time of 

 Garrett's pioneer studies; such changes were manifested not only in the 

 enlargement of their realms of occupation, but much more significantly in 

 the individual and colonial biological characters of the land-snails in question. 



The work of 1923 was in effect a re-survey of the entire island, and by 

 virtue of its more intensive nature it was successful beyond anticipation; 



