4^2 POPULAR SCIENCE MONTHLY. 



of one hundred and eight in a small specimen. Dr. Loeb has called 

 my attention to the more rapid absorption of oxygen in the light 

 than in the dark; this extended would probably mean the more 

 rapid absorption of oxygen through the skin of light-colored ani- 

 mals, a matter of doubtful value, however, to species living in 

 the dark. 



The gill filaments are small as compared with the gill cavity. 

 Oxygenation probably takes place through the skin. Ritter * 

 has suggested the same for Typhlogobius. 



" Cutaneous respiration is not unique in Typhlogobius and the 

 Amblyopsidse. In the viviparous fishes of California the general 

 surface, and especially the fins, which have become enormously 

 enlarged, serve as respiratory organs during the middle and later 

 periods of gestation; the fins are a mass of blood-vessels, with 



merely sufficient cellular 

 substance to knit them to- 

 gether. There is, however, 

 no pink coloration." 



Skin respiration would 

 account for the extreme re- 

 sistance to asphyxiation in 



Fig. \b.—Mancalias Sehufeldtii, 372 fathoms. Amblyopsis and TyphlogO- 



bius. About forty-five ex- 

 amples of Amblyopsis were carried in a pail of water four hun- 

 dred miles by rail, with only a partial change of water three times 

 during twenty-four hours. A smaller number may be kept for 

 days or weeks — probably indefinitely — in a pail of water without 

 change. The characteristics of Typhlogobius along this line have 

 been set forth elsewhere. 



Sticks, straws, etc., are never avoided by the fishes even when 

 perfectly imperturbed. By this I mean that they are never seen 

 to avoid such an object when it is in their path. They swim against 

 it and then turn. An object falling through the water does not 

 disturb them, even if it falls on them. A pencil gently moved 

 about in front of them does not disturb the fishes much, but if 

 the pencil is held firmly in the hand it is always perceived, and the 

 fish comes to a dead halt ten or fifteen millimetres before it reaches 

 such an object. On the other hand, they may be touched on the 

 back or tail before they start away. They glide by each other 

 leisurely and dignified, and if they collide, as they sometimes do, 

 they usually show no more emotion than when they run against 

 a stick. But this indifference is not always displayed, as we shall 

 see under the head of breeding habits. 



* Ritter, Museum of Comparative Zoology, vol. xxiv, p. 92. 



