404 M. A. Boeck on the Amj^hvpoda 



furnished on the upper surface with about twenty erect seti- 

 gerous tubercles. The flageUum consists of from thirty-four 

 (females) to forty-two (males) joints. The second joint of the 

 palpi of the maxillipedes is shorter than in E. cuspidatus, and 

 wants the teeth which characterize the latter. The hands of 

 the first pair of legs are of the same form as in E. cus2ndahis, 

 but rather rounder, and not so oval ; the three posterior pairs 

 of thoracic legs are very long ; the fifth joint is nearly as long 

 as the preceding two together, Avhilst it is considerably shorter 

 in cuspidatus. The outer branch of the fifth pair of abdominal 

 feet is only a little more than half as long as the inner one, 

 and the telson is less cleft than in cusjxidatus. 



Idanaj mihi. — Bruzelius described a Oammarus hrevicornis 

 from the Norwegian coast in general and from Bohuslehn ; 

 and Prof. Sars found a species in Finmark, which he named 

 Oammarus Jissicorms. Both species must be separated from 

 the genus Oammarus^ and placed under a new genus nearly 

 allied to Eusirus. The secondary flagellum, which in the 

 latter is very short, becomes extremely long in the two species 

 above mentioned, whilst the flagellum itself is short. The 

 inferior antennae are short and nearly subpediform. The mas- 

 ticatory tubercles of the mandibles are small ; and the inner 

 lamella of the first pair of maxilla3, as in Eusirus, is oval, and 

 furnished with isolated ciliated setaj. The masticatory lamellge 

 of the maxillipedes are small, and their palpi are much elon- 

 gated. The first two pairs of legs are furnished with strong 

 prehensile hands ; their fourth joint emits from its inferior 

 posterior angle a strong process, as in Leucothoe ; the following 

 pair of legs are very thin and long ; the last pair of legs are 

 very long ; the abdominal feet are long, and the telson deeply 

 cleft. The first epimera are strong, larger than the following 

 ones ; they consequently show much agreement with Eusirus, 

 and differ greatly from the typical species of Oammarus. The 

 two species may be easily distinguished from one another by 

 their different size, and also because the second and third seg- 

 ments in Iduna jissicornis are produced behind into a spine, 

 whilst in the other they are smooth. 



The ovigerous lamellai are of somewhat different size in this 

 group. In Leucothoe and Iduna they are small, .and the re- 

 spiratory lamellai long and broad ; in Eusirus the ovigerous 

 lamellai are broader than in the preceding ; and this is still 

 more the case in Sfenotho'e. In Leucothoe and Stenothoe there 

 is no secondary flagellum on the superior antennce ; in Eusirus 

 it is small, and in Iduna long. The mandibles are destitute 

 of palpi and masticatory tubercles in Stenothoe ; in Leucothoe 

 they have palpi, but no masticatory tubercles, which are small 



