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338 Mr H. Goodsir on the Sexes of the Cirripeds, SfC. 



IREN^US SPLUNDIDrS MIHI. 



Description. The whole animal gives forth a kind of luminous ap- 

 pearance, which is apparently caused by the splendid metallic colours 

 with which it is adorned. The prevailing colours are sappliarine and 

 emerald. The whole length is from about three to four lines ; and the 

 body, like those of other animals of the same family, is divided into two 

 great parts, the cephalo-thoracic, and the caudal or abdominal. The 

 head is as large as all the thoracic segments conjoined ; the thoracic 

 segments are six in number, and the abdominal are five. The head of 

 this animal is large and rounded superiorly and anteriorly ; it projects 

 downwards and forwards in the form of a rostrum. One pair of an- 

 tennae arise from the anterior part of the head ; they are hardly so long 

 as the thorax, and are very curious. 



The right differs from the left in being very much swollen about the 

 middle ; it may be divided into three parts ; the first or proximal is con- 

 siderably dilated, and is of an oval shape as far as the sixth articulation, 

 where it becomes much smaller, the four following being only about one- 

 third of the size ; the middle division of this antennae is also very much 

 swollen, but ispyriform, the largest part being jiroximal, and the contract- 

 ed distal ; this division is six-jointed, and the last joint, which is largest, 

 is deeply serrated on its inner edge. A large muscular or glandular body 

 runs from the base of this division to the proximal extremity of the first 

 articulation of the last division of the antennae. This last division is 

 composed of three articulations ; the first of these is the thickest, and has 

 a deep notch on its inner^edge, near to the basal extremity ; this articu- 

 lation is also armed on the same edge, but anterior to the notch, with a 

 number of spines. This curious mechanism seems to be adapted to 

 prehension, but whether it is used for this purpose or not is uncertain. 

 The notch appears to be a kind of hinge or joint, and the spines or ser- 

 rations on each side of it meet one another, so as apparently to make the 

 hold more firm. 



The left antennae is very different in its appearance from the right ; it 

 is composed of twenty-one articulations, is slightly swollen at its base, 

 but gradually tapers to its extremity. 



The tubular portion of the eyes is situated immediately behind the 

 rostrum; it i^ very large, rounded, and bulges at its extremity; it is ap- 

 parently sessile, is always directed downwards, and the colour is a 

 beautiful dark brown, with a shade of purple. A circular space at the 

 extremity is colourless, and sparkles brilliantl3% 



The foot-jaws, ten in number, are very similar to those of the Cetochilus. 

 The first is double both branches, arising from one common pedicle, 

 composed of two joints ; the external division is largest, and the extre- 

 mity of the second is armed with two rounded scales, the edges of which 

 are armed with a row of long fringed spines ; the internal division is 

 composed of two joints, which are much more slender than those of the 

 external, the extremity of the last being also armed with a scries of long 

 q,ud fringed spines or setae. The second pair of foot-jaws are composed 



