79 



The endopod (PI. XII, fig. 3«) has the very short basal part slender as a kind of stalk (.f.); 

 then it becomes extremely expanded and is distally divided into three large lobes. The undivided 

 broad part may be named the main plate (/«.), the three lobes respectively the inner (//.), 

 the median (lm.) and the setiferous lobe (Is.); from the base of the inner margin of 

 the setiferous lobe or between that lobe and the median projects a much smaller, narrow 

 auxiliary lobe (/«.). From a morphological standpoint the stalk, the outer part of the main 

 plate and the setiferous lobe may be regarded as the endopod itself, from the inner part of 

 which projects an enormous excrescence directed inwards and forwards (if seen in the natural 

 position on the animal it is directed inwards and downwards) and divided by a deep incision 

 into the inner and the median lobe, while the auxiliary lobe is a smaller protuberance beyond 

 the large excrescence; especially the shape of the organ in Stylocheiron (several figures on 

 PI. XVI) seems to confirm this interpretation. In specimens preserved in spirit and probably 

 also in living specimens the main plate with its lobes is rolled up from the inner side along 

 the setiferous lobe, and for the examination of the composing elements with the processes it is 

 necessary to unroll the whole organ and examine it from behind. 



The inner lobe, which is proportionately short, bears in Thysanopoda tricuspidata M.-Edw. 

 (PI. XII, fig. 3«) and several other species of the genus three strongly chitinized, slender 

 processes, all less or more movably articulated to the lobe: the spine-shaped process (p\) 

 on the inner margin somewhat or a little from the end, the terminal process (ƒ-.) on the 

 end, and the proximal process (p s .) on the outer side and longer from the end than the 

 spine-shaped process. The spine-shaped is 'always a slender, regular spine curved less or more 

 inwards at or before the middle (it is wanting in T cequalis H. J. H.; PI. XII, fig. 4<5); the 

 two other processes are longer and much thicker than the spine-shaped, and most varying in 

 shape in different species, sometimes even armed with several small, sharp teeth. The median 

 lobe is always much longer than the inner and furnished on the posterior side at or beyond the 

 middle of the inner margin with a less or more curved or distally quite hook-shaped 1 a t e r a 1 

 process (ƒ*.), and more distally at the same margin with a single smaller additional 

 process (p'\) or with two such processes. The auxiliary lobe has on the inner margin or on 

 the front side a number of quite minute, extremely curved coupling hooks. The setiferous 

 lobe is furnished on its rounded end and along a shorter or longer part of both margins with 

 a number of plumose setse, some of the most distal very long. 



In Euphausia (Pis. XIII & XIV, many figures) the organ is in the main as in Thysa- 

 nopoda, but in all species hitherto examined by me a spine-shaped process on the inner lobe 

 and additional processes on the median lobe are totally wanting. The terminal process has 

 generally a specially developed, transverse part, the foot (ƒ. on PI. XIV, figs. ib and 4c) 

 which sometimes is rather short, frequently long or very long, and from the outer end of the 

 foot projects in the proximal direction a free, short or long part, the heel (h. on the figures 

 just quoted), while the process itself projects in the opposite direction. The lateral process has 

 sometimes at or beyond the middle a sharp tooth (PI. XIV, fig. 2> c ) or even three teeth 

 (PI. XIV, fig. 6d). The distal part of the median lobe is frequently rather thin-skinned as in 

 Thysanopoda, but sometimes (E. psetidogibba Ortm., PI. XIV, figs. 40? — \e, and E. paragibba 



