PAN DE AZUCAR 101 



were not rich, although a number of mud-living 

 forms, especially worms and some excellent hy- 

 droids, were secured. Of mollusca, they took 

 several species of Tellina, one of Lavicardium, 

 some large Bulla, and a number of the Veneridas. 

 Among the dead mangroves bordering the main- 

 land Bartsch's party discovered a large rookery of 

 water-birds. Here they observed large numbers 

 of breeding Mexican cormorants, some of the nests 

 containing fresh eggs, while others had almost full- 

 grown young. Here also were noted the anhinga 

 or snake-bird; a pair of West Indian tree ducks, 

 breeding in an old tree; some American egrets, 

 the reddish egret, the snowy egret, the Louisiana 

 heron, the little blue heron, the Cuban green 

 heron, and a yellow-crowned night heron, all 

 having nests in this colony. In addition to these 

 they saw between two and three hundred white 

 ibis, but could not locate their nests, but it is 

 possible that the time of the visit did not coincide 

 with their breeding period. This rookery Bartsch 

 reported to be a rather large one, extending 

 over a little more than a mile of the coast, and 

 there appeared to be many thousands of birds 

 occupying it. 



