ALLAN HANCOCK ATLANTIC EXPEDITION 



REPORT 



Caledonia Bay ...... 7 



1 mile southwest of Cape la Vela ... 1 



2 miles southwest of Cape la Vela ... 2 



2 miles off Bahia Honda .... 5 



8 miles southwest of San Nicolaas Bay, Aruba 10 

 Tortuga Island ...... 8 



4 miles north of Tortuga Island ... 1 



Cubagua Island ...... 1 



3 miles north of Coche Island .... 5 

 Buccoo Bay, Tobago Island .... 1 

 7 miles north of Margarita Island ... 3 



As is usual in the American Tropics, the predominant family is the 

 Plumularidae with 10 species, but the Sertularidae follows closely with 9 

 species. There are only 5 species of gymnoblasts in the lot; if a more 

 extensive collecting of sargassum had been possible, the result in this 

 regard might have been different. 



Special mention should be made of 1 of the 6 species that are described 

 as new, Endothecium paucinodum. The Caribbean hydroids arrived from 

 the Hancock Foundation for examination with a large shipment of 

 hydroid material from the Eastern Pacific. As it happened the Pacific 

 material was examined first. In some of this, from the vicinity of the 

 Island of Anacapa, Southern California, specimens of a species of 

 Endothecium, not previously described, were obtained. As far as the 

 trophosome was concerned, these were fine specimens, and one of them 

 was figured and described. There was no gonosome observed on any of 

 them, hence it was taken for granted that the species was an Haleciiim. 

 Later, when the Caribbean material was examined, this same species 

 appeared. As far as the trophosome was concerned, the colonies were not 

 so fine as those from of? Anacapa Island, but some of them were complete, 

 with the gonosome present. Now it was evident that this was a species of 

 Endothecium. As the description of the trophosome held for these speci- 

 mens as well, this description has been retained, and to it has been added 

 the description of the gonosome from Caledonia Bay. 



Besides this one species common to both coasts, there are 16 others, 46 

 per cent of the records, practically all of which help to show more clearly 

 the route taken in extending the range from the West Indian and the 

 Caribbean Sea regions to the Eastern Pacific. The high percentage of the 

 species common to both coasts provides another addition to the accumulat- 

 ing evidence that much use was made of the passage or passages in earlier 

 times connecting the Caribbean Sea, or the Gulf of Mexico, with the 

 Pacific Ocean, as a well established distribution route. 



