60 



afsnit som Los Branchinecta, skjoiult deres indbyr- 

 des Længdeforliold er temmelig forskjelligt. 



Hovedet er forholdsvis af ringe Størrelse og 

 stumpt afrundet fortil. Det afgrændser sig skarpt 

 fra Xakkesegmentet, der til hver Side viser Skal- 

 kjertelen meget tydeligt. Triincus er stærkt for- 

 længet, regelmæssigt cylindrisk, og delt i ikke min- 

 dre end 19 vel begrændsede Segmenter, hvert bæ- 

 rende et Par Branchialfodder. 



Bagkroppen udmærker sig i hoi Grad ved sin 

 korte og plumpe Form, idet den neppe indtager 

 mere end '/s af Kropslængden. Kjonsringene er 

 fuldstændig sammensmeltede saavel indbyrdes som 

 med den bagenfor liggende Del af Halen, paa hvil- 

 ken alene det bagerste Segment er tydeligt be- 

 grændset. Hele dette Parti har, seet ovenfra (Fig. 

 2), en næsten pæredannet Form, idet det fortil er 

 stærkt fortykket og ligesom opblæst, med en afrun- 

 det knndeformig Protuberans til hver Side, medens 

 det bagtil gradvis afsmalnes. Breden over den for- 

 reste Del af dette Afsnit er mere end dobbelt saa 

 stor som Breden over selve Truncus. Sees Dyret 

 fra Siden (Fig. 1), viser sig Størsteparten af den 

 ventrale Side af dette Parti optaget af den volnmi- 

 nose Ægbeholder, hvis forreste Del er sæi'deles 

 stærkt hvælvet, medens den Imgtil kun rager ube- 

 tydeligt frem i Form af et kort koniskt Frem- 

 .spring. Paa Enden af dette Fremspring lindes den 

 ydre Aabning for Ægbeholderen, som hos Branchi- 

 necta, begrændset af 2 vertikale mod hinanden be- 

 vægelige Læber, hvoraf den overste er den største 

 og ender i en tilspidset Knude (se Tab. X, Fig. 12). 

 Halepladerne (se Tab. IX, Fig. 6) er forholdsvis 

 korte, neppe mere end dobbelt saa lange som de er 

 brede ved Basis, og viser en bredt lancetdannet 

 Form, med Spidsen smalt afrundet. De er hver 

 kantede med omtrent 19 cilierede Børster der suc- 

 cessivt tiltager i Længde mod Spidsen. 



Øinene (Tab. X, Fig. ], o) er forholdsvis korte 

 og tykke, neppe længere end Hovedets halve Brede, 

 og af den sædvanlige pæredannede Form, med Øie- 

 globen jævnt afrundet. Øiepigmentet er morkt, dog 

 iios det levende Dyr med et tydeligt purpurrødt 

 Skjær, og de enkelte Synselementer vel udviklede. 

 Det enkle Øie sees som en tydelig mork Plet i Mid- 

 ten af Hovedets Pandedel. 



Første Par Følere (Fig. I, a', Fig. 3) er for- 

 holdsvis bet3'delig kortere end hos Branchinecta, 

 neppe halvt saa lange som Øinene, men viser for- 

 tjvrigt en meget lignende Bygning, og bærer paa 

 Spidsen de sædvanlige Lugtepapiller og Følebørster. 



Andet Par Følere (Fig. 1, a'0 er ligeledes min- 

 dre end hos Branchinecta, og har Formen af 2, som 

 det synes, fuldlcommen ubevægelige trekantede Flige, 



same body-divisions can be disGnguished a.s in Bran- 

 chinecta, although their mutual relations as to length 

 are rather diiferent. 



The head is comparatively small and Ijluntly 

 rounded in front. It is shar])ly defined from the 

 cervical segment, which shows the shell-gland on 

 each side very distinctly. The trunk is greatly 

 elongated, regularly cylindrical, and divided into no 

 less than 19 well-defined segments, each bearing a 

 pair of branchial legs. 



The posterior part of the body is highly remar- 

 kable for its short and stout form, constituting, as 

 it does, scarcely Vs of the length of the body. The 

 genital segments are completely coalesced, both 

 mutually and witli that part of the tail posterior 

 to them, in which only the hindmost segment is 

 distinctly defined. Tlie whole of this part, seen 

 from above (fig. 2), is almost pyriform, being very 

 much thickened in front, and as it were inflated, 

 with a roiinded, nodiform protuberance on each side, 

 while po.steriorl}' it tapers gradually. The breadth 

 of the front part of this section is more than double 

 as great as that of the trunk itself. AVhen the 

 animal is seen from the side (fig. 1), the greater 

 part of the ventral side of this region ajipears to be 

 occupied by the voluminous marsupiiim, the anterior 

 part of which is boldly convex, while the posterior 

 end projects only slightly in the form of a short, 

 conical prominence. At the end of this jn'ominence 

 is seen the external opening of the marsupium, 

 bounded, as in Branchinecta, by 2 movable lips, the 

 upper of which is the larger, and ends in a pointed 

 nodule (see PI. X, fig. 12). The caudal lamellæ 

 (see PI. IX, fig. G) are comparatively short, being 

 scarcely more than double as long as they are broad 

 at the base. They exhibit a lu'oadly lanceolate shape 

 with the point narrowly rounded, and are eacli 

 fringed with aliout 19 ciliated lu-istles, which suc- 

 cessively increase in length towards the jioint. 



The eyes (PL X, fig. 1, o) are comparatively 

 short and thick, scarcely longer tluxn half the 

 breadth of tlie liead, and of the usual jiyriform 

 shape, with the eye-ball evenly rounded. The jjig- 



ment is dark, tl 



lOUU'll w 



itli a di.stinct tinsre of crim- 



son in the living animal: the visual elements are 

 well-developed. The ocellus is observable as a dis- 

 tinct dark spot in the centre of the frontal part of 

 the head. 



The fii'st jiaii' of antennæ (ligs. 1, a' and 3) are 

 comparatively mucli shorter than in Branchinecta^ 

 being scarcely half as long as the eyes, but in 

 other ways exhibit a very similar structure, and 

 carry at the extremity the usual olfactory' papillæ 

 and sensory bristles. 



The second pair of antennæ (fig. 1, a") are also 

 smaller than in Branchinecta, and have the form of 

 2 apparently ])erfectly iminovahle triangular lappets 



