THE ENTOMOLOGIST. 531 



Latreille, that the Chinese eat the eggs of a species of Limulus 

 which inhabits their seas. 



The structure and entire appearance of the king crab is so 

 different from that of a crab, in the ordinary acceptation of 

 the term, that I think 1 may be allowed to say a few words in 

 the way of definition, premising, however, that my knowledge 

 of the creature is almost exclusively derived from books; 

 for, although I have possessed from time to time many speci- 

 mens of Polyphemus, I have never studied them with a view 

 of making an accurate and detailed description. 



Laying the creature on its back, as in fig. 1, the anterior 

 margin of the shell, a a, presents a flattened edge, which is 

 distinct and well defined in the middle, but vanishes towards 

 the extremities: below this margin is a flattened area, i, 

 bounded below by two arcuate lines, which meet in the 

 middle at a small tooth or button, comparable to the key- 

 stone of an arch ; in the figure this is equidistant from the 

 letters b,dd: below this flattened area is a considerable 

 concavity, in the centre of which, n, is an obvious aperture, 

 called the "pharynx," by general consent of entomologists, 

 and around this are arranged, in a somewhat radiating 

 position, twelve limbs, each of which terminates in a didactyle 

 claw, very similar lo those with which one or more pairs of 

 the legs of decapod crustaceans are usually furnished. These 

 limbs vary considerably in size and length, but they scarcely 

 ever project beyond the margin of the shell, and are con- 

 cealed when we look at the back of the animal (see fig. 2, 

 p. 534). We search in vain for antennae, palpi, mandibles, 

 or maxillae, of the usual crustacean character, and it is, 

 possibly, from this apparent absence of these familiar organs, 

 that entomologists have thought it desirable to assign the 

 functions, or at any rate the names, of these organs to one or 

 other pair of the twelve limbs, but there is little accord 

 among authors in this repect. Notwithstanding the manifest 

 difference in the length and size of these limbs, there is an 

 obvious similarity in their form and fashion, as will be very 

 observable in the figure (fig. 1) which I have copied from 

 Savigny. The first pair of limbs, dd, are very much shorter 

 and smaller than those which follow, and seem to consist of 

 only two joints: Jimty the basal joint, seated on a small 

 flattened plate, which has been called the upper lip or 



