50 THE VOYAGE OF H.M.S. CHALLENGER. 



which overlap on the middle line. The endopodite of the first abdominal appendage of 

 the male is shown in PI. X. fig. 12. It is very much smaller than the exopodite, 

 triangular, and as wide as long. The inner lobe b of the terminal joint is very small, 

 nearly circular, and separated by a suture from the broad triangular outer lobe a. The 

 movable limb of the petasma is long, nearly straight, and armed on its outer edge, near 

 the base, with an acute spine, while the fixed limb is very short and without a hook at 

 the tip, which is rounded, as is the case in Lysiosquilla maculata. The sexes of this 

 species are quite different from each other, and it seems probable that secondary sexual 

 differences may occur in all the flat loosely articulated Stomatopods. 



The character of the difference between the sexes is however quite diflFerent from 

 what we find in Lysiosquilla maculata. In the latter species the sexes are alike in size 

 and colour, and they diflfer in structural features, while in this species there are no 

 structural differences except those which are concerned in reproduction, but the female is 

 much larger than the male, and of an opaque oUve brown, almost black colour, while the 

 male is of a transparent grey. 



Habits. — As our information regarding the habits of the Stomatopoda is very 

 scanty, I give aU that I have been able to learn of the habits of this species. It is found 

 in the sand of the ocean beach just below low-tide mark, where it is exposed to the full 

 force of the ocean swell, and it inhabits a very deep cylindrical burrow which is nearly 

 vertical and goes down for several feet. While watching for its prey the animal stations 

 itself at the mouth of the burrow, which is arched over with sand, so that only the tips 

 of the eyes are exposed. The food consists of small Crustacea, fishes and other small 

 animals, and when one approaches within reach the Coronis darts out of the burrow, 

 knocking away the loose sand, and seizing it in its raptorial claw it darts backwards with 

 it and retreats to the bottom of the burrow. When hungry it often captures prey at a 

 distance of six or eight inches, but, as a rule, it waits until it is near enough to be caught 

 without leaving the opening. The food which is captured is usually stored away at the 

 bottom of the burrow, and the animal returns to the mouth and resumes its watch. In 

 excavating its burrow the animal begins by stretching its body out on the sand, which is 

 then swept away from under it by the action of the abdominal appendages, until all of 

 the body exc^t the eyes and telson are buried. It then forces its head into the loose 

 sand which has been stirred up by the action of the abdominal appendages, and dragging 

 its body down it quickly becomes buried vertically, head downwards, and it continues to 

 burrow until it reaches the hard undisturbed sand, when it bends upon itself, and passing 

 the head up on the ventral side of the swimmerets it reverses its position and works 

 upwards to the surface, hardening and compressing the sand by the pressure of the dorsal 

 surface. After the upper end of the 'burrow is thus rendered firm and circular it again 

 doubles upon itself, and going to the bottom gathers an armful of sand, which is clasped 

 against the ventral surface of the body between the large second maxiUipeds, where it is ( (P. 5"' 



