125 



but they were so timid, and active in their movements, that I 

 could not procure a specimen. The stomach contained a great 

 many varieties offish; among them a cottus, a parrot-lisli, Hatfish 

 of two species, and some hirge prawns ; but their principal food 

 seemed to be fiying-fish, and a species of hemirhamphus. 



Dissection. Heart hirge. Right lobe of liver, as usual, the 

 largest; .085 in length, by .040 in breath. Left lobe .052 in 

 length, by .025 in breadth. Gall-bladder elongated, and rather 

 large. Pancreas lying between the two folds of the duodenum. 

 Stomach enormous, occupying nearly the whole left side of the 

 abdomen, extending from the heart to the cloaca, measuring, when 

 entirely empty, .10 in length, by .06 in breadth. Intestines veiy 

 large, 1.5 in length ; ca^ca very small. Tlie difference between the 

 digestive organs of this bird and the fish-hawk is very marked, and 

 is a good example of the various ways that nature takes to effect 

 the same purpose ; the food of both birds being the same. The 

 intestine of the fish-hawk, which is the smaller bird, measuring 

 2.8 in length, nearly twice that of the booby, while its diameter 

 is not more than one half as great. 



Sida dactylatra, Lesson ? Lesson's description of this bird is 

 not sufficiently full to enable me to decide, with certainty, whether 

 it is the same as those I procured at the Bahamas. If it should 

 prove to be a new species, the name elegans would be appropriate, 

 as it is the prettiest of the genus. In dimensions, it is about the 

 size of the Sula fusca, but heavier and more muscular. I found 

 them breeding but at one place, — St. Domingo Kay, — and there 

 only some twenty pairs. They apparently lay their eggs later • 

 than the booby, as the largest of the young were not more than 

 half grown, and the eggs of several were freshly laid. As in the 

 booby, the number of the eggs was two. They were whiter than 

 those of the latter bird, the chalky covering being much thicker, 

 and did not differ as much in size or proportions ; the two extremes 

 measuring .066 by .045 and .062 by .044. They did not associ- 

 ate with the other species. The young birds and eggs were all 

 in one part of the island. When half fledged they are very 

 pretty, the snowy-white down with which they are covered form- 

 ing a striking contrast with the dark brown of the tail and wings 

 then just appearing. Their habits are precisely the same as those 

 of the boobies, and their internal structure presents no appreci- 

 able difference. 



