72 EVENINGS AT THE MICE0SC0P13. 



are quite bewildering. I must act the showman, and 

 tell you what to see. 



Tlie cells are ohlono;, shaped much like a sack of 

 corn, with a spine ascending from each of the upper 

 corners. Each stands on the summit of its predecessor 

 in the same row, and side by side with those of its fel- 

 low-rows, in such an order that the top of one cell comes 

 opposite the middle of the one beside it. The top of 

 the sack is rounded, and appears closed, but we shall 

 presently find an opening there. The broad side that 

 faces inwardly has a lai'ge elliptical transparent space 

 occupying nearly its whole surface ; this is covered 

 with a very thin and elastic membrane, and answers a 

 peculiar end. Just below one of the spines that crowns 

 the summit of tlie cell on one of the edges, is situated a 

 little lump, to Mhich is attached, by a very free joint, 

 an object which you will perceive to bear a remarkable 

 resemblance to the head of a bii'd of prey. It has a 

 beak strongly hooked, with two well-formed mandibles, 

 of which the lower is movable, shutting into the cavity 

 of the upper ; you observe it deliberately opening, like 

 that of a bird, onlv stretchin<>; to an enoi'mous width of 

 gape, and then closing with a strong and sudden snap. 

 Now and then the whole head sways backward and for- 

 \vard on its joints ; and these movements, combined 

 with the fitful and apparently spiteful snappings, per- 

 formed by many birds' lieads scattered about the 

 bi-anch, are highly curious and amusing. 



The birds' heads, however, are not the living inhab- 

 itants of the cells ; they are not integral parts of them. 

 The cells have their proper inhabitants, each dwelling 

 in its own ; and each essentially formed on the same 

 plan as the "baby Mith the tucked-up knees," that 

 makes the Sea-mat for his cradle-house. 



