42 



Gr. 0. SAES. 



[No. 8. 



proximal part of the tail, are of moderate length and distinctly 

 bi-articulate, with the outer joint densely ciliate. 



The intestine forms, as usual, in the posterior part of the 

 trunk, a double loop (see Pl. 7, fig. 1), and becomes somewhat 

 dilated before joining the rectum, without, however, exhibiting 

 any distinct cæcal appendage. The anal orifice occurs on the 

 dorsal side of the caudal plate, near its base. 



The ova in the matrix would seem not to exceed two in 

 number. They are both of a regular oval form, and, as a rule, 

 disposed one behind the other. 



The male (Pl. 7, fig. 6) is very much smaller than the 

 female, scarcely exceeding 0,46 mm in length, and may easily be 

 distinguished from the latter by the relatively greater size of 

 the antennulæ, projecting, as they do, considerably bey ond the 

 apex of the rostrum, as also by the structure of the Ist pair 

 of legs (fig. 7), armed with a powerful, anteriorly curved hook 

 originating on the trunk between the exopod and endopod, 

 and extending as a rule beyond the valves of the carapace 

 anteriorly. 



The body of the full-grown female is amber-coloured, with 

 a more or less distinct reddish tinge, that of the male being 

 much paler and well-nigh colourless. The eggs recently depos- 

 ited in the matrix of the female are of a dark-greenish colour. 



Observations. — This is a true limicole form, its habitat 

 generally occurring within the loose bottom deposit, through 

 which it forces its way partly by means of its antennæ, partly 

 and principally by its powerful tail, the very mobile terminal 

 section of which acts as a most effective organ of locomo- 

 tion. At times, the animal also moves about freely through the 

 water; but this mode of locomotion is never found to last for 

 any length of time. It swims on its back; and by rapidly 

 repeated strokes of the antennæ the body is propelled through 

 the water, till it reaches some object which, as a rule, it 

 succeeds in climbing up by means of the curved bristles affixed 

 to the exopod of the 2 first pairs of legs. 



I first observed this form on returning from my excursion at 



