occurring on tlte Norwegian Coasts. 405 



in Iduna and large in Eusirus. In Leucothoe and Stenothoe 

 the two joints of the first pair of maxilLary palpi are of equal 

 length ; in Eusinis this is nearly tlie ease ; in Iduna the fii'st 

 joint is short. The inner lamella is larger than the other in 

 Eusirus and Iduna, but in all only furnished with one bristle; 

 in all, the first two pairs of legs are of a peculiar form, iuAvhich 

 they resemble G^dicerus, but differ among themselves some- 

 what in form. The remaining legs are long and slender in 

 all. The telson, which is entire in Stenothoe and Leucothoe^ 

 is cleft in Eusirus and divided in Iduna. 



Dexamine, Leach. — This genus agrees in some respects 

 with the preceding. As in it, the palpi of the maxillipedes are 

 very thin, but the fourth joint, which in Iduna was long, and 

 even divided into two joints, appears here to be wanting ; the 

 masticatory tubercles are very strongly developed ; the inner 

 lamella in the first pair of maxillae has only a single bristle, 

 but the palpus is of one joint ; the fonn of the ovigerous and 

 res})iratory lamellae is as in the preceding ; as in this, the 

 third joint of the peduncle of the superior antennae is short ; 

 in the structure of the legs it approaches Gammarus. Besides 

 the species D. tenuicornis, H. R., I have found a new spe- 

 cies : — 



D. thea. — The superior antennae reach to the second seg- 

 ment of the abdomen. The first joint of the peduncle is not 

 l)roduced downwards into a process ; the flagellum consists 

 of eighteen very long and slender joints ; the inferior antennaj 

 are shorter than the superior ; their peduncle is very thin, and 

 its fifth joint is somewhat longer than the fom'th ; the flagellum 

 is formed by from twelve to fomteen long joints; the eyes are not 

 very large, but oval ; the parts of the mouth are rather longer 

 and slenderer than in D. tenuicornis] the first joint of the 

 seventh pair of legs is very slender, not dilated as usual, and 

 not broader than the following joint ; the last thoracic segment 

 and the first four abdominal segments are produced into a 

 strong spine ; the fifth pair of abdominal feet are mucli shorter 

 than in the other species, and do not extend further back than 

 to the branch of the last pair of abdominal feet. 



In the following genera the inner lamella of the first pair of 

 maxillai is furnished with many ciliated hairs, and the ovi- 

 gerous lamellai are very broad. 



Epidesura, mihi. — The type of this new genus is Lilljeborg's 

 Amjdiithoe compressa, which, in the breaking up of the genus 

 ^•l»y^Z!<V/!fi', must stand by itself ; it approaches the preceding 

 genus in several characters. The form of the antenna} is as 

 in the preceding ; the mandibles, which in Dc.raminc are de- 

 stitute of palpi, have t'lem here very thin, weak, and tlu'ce- 



