No. 629] HABITAT RESPONSES OF WATER-STRIDE R 501 



luivior under consideration was found in a ])ai)('r liv 

 Drzewina (1908) on the ]iydrotroi)isni of ci ahs. Caimni.s 

 mccnas. Because of the character of this woik, I shall 

 refer to it and quote from it at some length. This wi iter 

 makes a careful analysis of the responses of these crusta- 

 ceans to the sea. She noticed that when one of the crabs 

 was placed on the heach that it oriented itself and moved 

 toward the sen. even at a .listaucc of 100 iiu-ters. Her 

 statcincnt ( IHOS. pp. Kin'.i Inlli) Inllcws: 



Her observations seem to i)rove tiiat both onciitatioii to 

 and direction of inovement towai-d the sea wi're not (hie 

 to resi)onses to light, to the sight of the sea, to the wind, 

 or to gravity, but on tlie other hand were due to the mois- 

 ture given off by the sea. Observations w^ere made every 

 dav foi- nioi'c than a month, at ditTerent times of the day, 

 both 111 l)i iiilit snnliuiit and also in cloudy weather. These 

 facts me hioii-li! out in the following quotation (1908, 

 1). iniO) : 



