. AMPHIPODA AND ISOPODA OF THE FIRTH OF CLYDE. 31 



During the summer months the females are mostly 

 with ova, which some of them appear to produce 

 when very young. The number of ova carried is 

 generally about eight. They carry the young under 

 their body for a time, but these are not readily 

 seen till the parent is put into spirits, when the 

 young drop out. It occasionally happens that one 

 or two females with ova are greatly larger than 

 the others. There are others in the same gather- 

 ings of smaller make, with long thin under-antennse ; 

 these I take to be the males of the same species. 



To try how they would behave in fresh-water, 

 three of the females were put into a cupful, where 

 they at once dropped motionless to the bottom. 

 After having lain for a few seconds, they rose, 

 making a few gyrations till they reached the 

 surface, and then dropped gently down to the 

 bottom, where they remained motionless. When 

 disturbed they again performed their upward gyra- 

 tions, dropping to the bottom as before ; but in the 

 course of fifteen or sixteen minutes they were 

 unwilling or unable to rise up into the water, 

 making only a few curving movements on the 

 bottom. In twenty minutes they only showed life, 

 and in half an hour they were dead. 



The tracks made in the sand by this species 

 formed the subject of observation by Mr. Hancock, 

 as described in his Memoir on Vermiform, Fossils, 

 read at the meeting of the British Association at 

 Leeds, September 22nd, 1858.* I have found Kroyera 

 arenaria to be the chief burrow-maker here. 



kroyera altamarina, Spence Bate and Westwood. 



Kroyera altamarina, Spence Bate and Westwood, 

 Brit. Sessile-eyed Crust., p. 177. 



Habitat— Dredged off Callum's Bay, Bute, in 16 

 fathoms, mud and shell debris. Not common. 



*S. Bate and Westwood, Brit. Sessile-eyed Crust, vol. i., p. 175. 



