1 8 Cruise of the "Alert." 



we obtained some Globigerina forms, several Crustaceans, some 

 minute Pteropods of the genus Cuvieria, and a host of minute 

 Confervae, of the kind met with previously to the northward of 

 Madeira. On the afternoon of the 5 th of November, when we 

 were about a hundred miles from St. Paul's Rocks, we noticed 

 that the little petrels, which for weeks had accompanied us in 

 great numbers, were now feebly represented, and in the evening 

 were completely gone. Perhaps they had found out their proxi- 

 mity to terra firma, and were gone for a run on shore. It is 

 very strange how these birds, which follow ships over the ocean 

 for thousands of miles, can manage to time their journeys so as to 

 reach land for their breeding season. That the same individuals 

 do follow ships for such great distances we have good evidence ; 

 for Captain King, in his voyage of the Adventure and Beagle, 

 mentions a case in which the surgeon of a ship, coming home 

 from Australia, having caught a Cape pigeon (Dapteon capensis), 

 which had been following the ship, tied a piece of ribbon to it 

 as a mark, and then set it free. The bird, recognized in this way, 

 was observed to follow them for a distance of no less than 5,000 

 miles. 



From the last date to the 9th of November, but little of interest 

 occurred. One day a petrel {Thalassidroma pelagicd) had been 

 caught with a skein of thread ; and on opening the body the 

 crop was found to contain a number of stony particles, bits of 

 cinders, minute shells, and otolites of fishes. In the tow-net we 

 caught a number of Rhizopods, of ■£$ inch diameter, which kept 

 continually unfolding and shutting up their bodies in telescopic 

 fashion. When quiescent, the animal is egg-shaped, and about 

 the size of a mustard seed ; but when elongated, it is twice that 

 length, and exhibits a tubular sort of proboscis armed with an 

 irregular circle of vibrating cilia. We also obtained a Pteropod 

 resembling the Criseis aciculata, an Ianthina, and some hyaline 

 amcebiform bodies, which were entirely beyond my powers of 

 recognition. On the following day we got more of the pretty 



