Development of Estheria Packardi. 25 



effected by the aid of the antennæ, the outer part of which, 

 together with the head, being extruded from the shell anter- 

 iorly, and the rami violently moved sidewards. Not infrequetly 

 the animal was seen to move in this manner rather slowly 

 along the bottom, the back upwards, whereby the muddy 

 particles were whirled up around it and partly thrown inside 

 the shell. This proceeding being often repeated, it would 

 seem that it was effected chiefly for the purpose of feeding. 

 In the same aquarium, in which the above-mentioned 

 female specimen occurred, two male specimens were also 

 reared, both apparently attaining to their full size, though 

 being somewhat smaller than the female. They were often 

 seen eagerly pursuing the female, and in one case one 

 of the males got a rather firm hold on the female by inserting 

 the strong claws of his 2 anterior pairs of legs inside the 

 shell of the latter, at its upper posterior corner. The 2 

 sexes remained for rather a long time locked together in this 

 manner, but wether a true copulation thereby took place, I 

 could not ascertain. The specimens, after having been sub- 

 jected, to a closer examination under the microscope, were 

 replaced in the aquarium, but they did not live long after- 

 wards, and their empty shells were subsequently found on 

 the bottom of the aquarium 



Explanation of the plates. 



PI. I. 



Fig. 1. Recently hatched larva (1st larval stage), viewed 

 from the dorsal face; magnified 120 diameters. 



