Occasional Papers of the Musenin of Zoology 9 



to avoid remaining in a very strong current. \Mien conhned 

 in an ac[uarium containing a pile of smooth glass objects the 

 lamprev sho^\•s little or no inclination to retreat among them, 

 l)ut it will at once hide among stones. If a number of them 

 are placed in bright light in a dish one-half of which is cov- 

 ered \vith ruby glass, they are at hrst active but soon collect in 

 the area of red light and come to rest. It seems tlien that the 

 preference for weak light determines the burrowing habit. 



The spawning nests are very ill-defined ; they are little more 

 than areas on the stony l)ottom where the sand and pebbles 

 have been cleared away from between or beneath larger stones. 

 Other nests three or four inches in diameter and of about the 

 same depth are sometimes excavated in sand or gravel. Dur- 

 ing the excavation of such a nest the lamprey's body is nearly 

 vertical. \\ ith no tendency to incline in a particular direc- 

 tion with respect to current. The pebbles are thrown out in 

 any direction. Although the excavation of nests is prosecuted 

 with great vigor, with sometimes as many as seven or eight 

 individuals present, attempts at spawning in them are rarely 

 seen. On the contrary, tlie spawning act takes place almost 

 invariably when the animals are more or less hidden among 

 stones. Consecjuently it has been dihicuit to determine the 

 exact details of the act. Apparently the male attaches him- 

 self by the l)uccal funnel either to a stone close to where the 

 female is likewise attached, or to the body of the female near 

 her head. Then the l)odies of both are tln'own into spasmodic 

 vibration. At the same time the eggs may be seen to escape. 

 Some of them are carried down by the current. The male, so 

 far as our observations go, seldom v\"inds his tail about the 

 female. Infrequently an individual may wind his tail about th.e 

 head of another, vibrating his bod\' at the same time, or may 

 seize another near the branchial region, wind his tail aroimd 



