330 M. A. Boeck on the Ampkipoda 



however, quite certain as to the correctness of his statement, 

 as his notes are lost ; but the structure of the animal seems to 

 strengthen it. The largest individual measured 45 millims., 

 and it is therefore one of the largest of the Amphipoda. The 

 body is strongly made, somewhat compressed laterally ; the 

 back round, without a keel ; the head projects forwards in a 

 long and broad rostrum, which covers the basal parts of the 

 superior antenna; ; the eyes are very large, and occupy, as in 

 the Hyperidoe, nearly the whole of the sides of the head, and 

 are nearly contiguous above; the superior antenna; are the 

 shortest ; the peduncle small and short ; the flagellum formed 

 of a somewhat long first joint, clothed with hair on the inner 

 surface, and of from twelve to fourteen other shorter joints ; the 

 secondary flagellum likewise consists of a long first joint, and 

 of two much smaller following joints. The inferior antenna; 

 are one-third longer than the superior ones ; the first three 

 joints of the peduncle are very short, the two following ones 

 longer and equal in length, the first serrated on its lower sur- 

 face ; the flagellum consists of twenty joints. They therefore 

 agree with the antenna; of the Hyperidce and of the genus 

 Anonyx. The parts of the mouth appear as an extended trifid 

 tube, which is formed by the extraordinarily produced labrum 

 and the transformed outer lamella; of the maxillipedes. Within 

 this tube (from which the generic name is derived) are the 

 acute, much-produced, but weak mandibles and maxilla;, which 

 resemble a kind of prickles. The maxillipedes are furnished with 

 four-jointed and the mandibles with three-jointed palpi. The 

 first pair of feet are converted into strong prehensile organs of 

 peculiar structure ; the fifth joint, or hand, is very large, in- 

 flated, and attached by its inner side to the preceding joint. 

 The claws are not, as usual, attached to the lower angle, apply- 

 ing themselves against the hinder margin with their points 

 upwards, but attached to the hinder upper angle, with the 

 points downwards — thus agreeing somewhat with Kroyer's 

 genus Opis. The second pair of feet is formed as in the genus 

 Anonyx ; the third and fourth pairs are dissimilar ; the first 

 and, especially, the third joint of the fourth pair are strongly 

 dilated into a shield-like form, whilst those of the third pair 

 are narrower ; the three following pairs are of the usual struc- 

 ture, and gradually increase in length. The abdomen is very 

 broad, and closely agrees in its form with that of the Hyperidce- 

 but the three posterior pairs of abdominal legs have the pe- 

 duncles shorter than in the latter. The second pair of epimera 

 are particularly large, triangular, with the base downwards 

 and the obtuse apex upwards, and nearly conceal the first pair. 

 The animal thus resembles the Hyperida; in the structure of 



