260 EVEXESTGS AT THE MICROSCOPE. 



You are then prepared to take a peep at tliis beau- 

 tiful Brachiomis pala, A cup of elegant form, s-welling 

 at the sides and narrowing a little at the' mouth, has 

 one side of its rim furnislied Tvith four spines, the mid- 

 dle pair of which are very slender, sharp, and needle- 

 like ; the other side of the rim is undulated, hut not 

 toothed. The bottom of the cuj) terminates in two 

 broad blunted points, — when seen directly in front ; 

 but a lateral view considerably modifies the whole form. 

 Tlien you see that the back of the cup is much more 

 swollen, the belly-edge being nearly straight, and that 

 this latter descends much lower than the dorsal line, the 

 bottom being as it were cut away obliquely and slightly 

 hollowed. Between the two bottom points, there is a 

 round opening, for an object which we shall see pres- 

 ently. Such is the shell, or lorica, as it is technically 

 called, which is of a rather stifi", elastic consistence, of 

 a horny (chitinous) texture, and of the most glassy 

 transj)arency, permitting us to trace every vessel, every 

 organ, and every function of the animal within the shell 

 with perfect distinctness. The little creature is of un- 

 wonted d imensions in its class, for it is one thirty-sixth 

 of an inch in length. Hence it is just visible as a white 

 speck moving in the water, to the unassisted eye, while 

 a pocket lense reveals its beautiful form. 



Within this translucent shell you see a confused 

 mass of moving viscera, a multitude of irregular sacs 

 and bands, lying over each other, whose crowding, 

 changing, and vanishing lines distract the attention, and 

 prevent you from making out anything definitely. But 

 a waved outline of hyaline flesh is protruding from the 

 rim of the shell, and now, having reached beyond the 

 level of the spine-points, it rapidly unfolds into three 



