occurring on the 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 Eusirus this is nearly the case ; in Iduna the first 

 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, in which 

 they resemble (Edicerus, 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 maxilla? has only a single bristle, 

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

 respiratory lamellae is as in the preceding 5 as in this, the 

 third joint of the peduncle of the superior antenna3 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 antenna? reach to the second seg- 

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

 produced downwards into a process ; the flagellum consists 

 of eighteen very long and slender joints ; the inferior antenna? 

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

 its fifth joint is somewhat longer than the fourth ; the flagellum 

 is formed by from twelve to fourteen 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 much 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 

 maxilla? is furnished with many ciliated hairs, and the ovi- 

 gerous lamella? are very broad. 



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

 Amphithoe comjyressa, which, in the breaking up of the genus 

 Amphithoe, 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 Dexamine are de- 

 stitute of palpi, have them here very thin, weak, and three- 



