26 NATURAL HISTORY OF 



which SO much has been written. According to one of the 

 most recent investigators of the subject, M. Lacaze-Duthiers, 

 the float " is increased by complicated movements of the 

 anterior part of the feet, which result in forming an air-bubble 

 enclosed in a glutinous matter," and the lanthina cannot 

 produce a float as long as it is beneath the surface of the 

 water. A fine specimen of this beautiful creature, captured 

 in the towing-net, proved to be the I. globosa, and had two 

 specimens of a small Lepas attached to its fragile shell. A 

 species of Porpita was also present in great abundance, and 

 a number of specimens were taken and consigned to spirits. 

 On the morning of the 16th a large flying-fish came on board, 

 but I had not an opportunity of examining it, gastronomy 

 having prevailed over zeal for science before I was out of bed. 

 A curious parasitic crustacean {Geratothod) found in its 

 mouth was, however, preserved and presented to me. 

 Several Pteropoda also occurred in the towing-net, chiefly 

 species of the genus Pneumodermon, as well as several speci- 

 mens of a curious aquatic insect of the genus Halohates, which 

 swims about on the surface of the sea in the same manner as 

 some of its allies do on that of fresh-water streams. Some 

 swallows were seen at this time, and a young individual was 

 caught. The poor little bird was much exhausted, and drank a 

 little water eagerly, but would not eat, and on being afterwards 

 let go, it flew for some distance and then fell into the water. 

 On the 18th I only obtained a few Acalephae, and my towing- 

 net work was brought to a close by our getting up steam, 

 owing to the failure of the breeze which had thus far accom- 

 panied us. A grasshopper was brought to me in the course 

 of the day, but possibly it had travelled with us from St. 

 Vincent. 



On the morning of the 19th a small Remora {Echeneis 



