NARRATIVE OF THE CRUISE. 259 



light, the pupil on the one side was contracted almost to a speck, whilst that on the 

 other was widely dilated. The birds are subject to great variations in the amount of 

 light they use for vision, since they feed at sea by night as well as by day. It seems 

 remarkable that there should be only one species of Penguin at the Tristan da Cunha 

 group, since in most localities several species occur together. It would seem probable 

 that a species of Jackass Penguin {Spheniscus) should occur on the islands, since one 

 species (Spheniscxis magellanicus) occurs at the Falkland Islands and Fuegia, and another 

 (Spheniscus demersus) at the Cape of Good Hope, intermediate between which two points 

 Tristan da Cunha lies. The connection between these two widely-separated Sphenisci is 

 wanting ; perhaps it once existed at the Tristan group, but has perished. Most of the 

 droves of Penguins made for one landing place, where the beach surface was covered with 

 a coating of dirt from their feet, forming a broad track, leading to a lane in the tall grass 

 about a yard wide at the bottom, and quite bare, with a smoothly beaten black roadway ; 

 this was the entrance to the main street of this part of the "rookery," for so these 

 Penguin establishments are called. Other smaller roads led at intervals into the rookery 

 from the nests near its border, but the main street was used by the majority of the birds. 

 The birds took little notice of their visitors, allowing them to stand close by, and even to 

 form them into a group for the photographer. A very successful photograph of a 

 group of the birds standing near one of the entrances into the forest of Tussock 

 forming the rookery is reproduced in PI. VII. This kind of Penguin is called by the 

 whalers and sealers " rockhopper," from its curious mode of progression. The birds 

 hop from rock to rock with both feet placed together, like men jumping in sacks, but 

 they scarcely ever miss their footing. When chased, they blundered and fell amongst the 

 stones, struggling their best to make off. 



Immediately on entering the main street of the rookery the explorer is as if in a 

 maze, and cannot see in the least where he is going. Various lateral streets lead off on 

 each side from the main road, and are often at their mouths as big as it ; moreover, the 

 road sometimes divides for a little and joins again, hence it is the easiest thing in the 

 world to loose the way, and this is quite certain to occur to persons inexperienced in 

 Penguin rookeries. The Germans who acted as guides, accustomed to pass through 

 the place constantly for two years, were perfectly at home in the rookery, and knew 

 every street and turning. It is impossible to conceive the discomfort of traversing 

 a big rookery, hap-hazard, or "across country" as one may say. A plunge is made 

 into one of the lanes in the tall grass, which at once shuts out the surroundings from 

 view. You tread on a slimy black damp sod composed of the birds' dung. The 

 stench is overpowering, the yelling of the birds most annoying and discordant. You 

 lose the path, or perhaps are bent from the first in making direct for some spot on 

 the other side of the rookery. In the path only a few droves of Penguins, on their 

 way to and from the water, are encountered, and these stampede out of your way 



