125 



De 2 folgende (9de og 10de) Par (se Fig. 3) 

 mangler, ligesom det sde, ganske Epipodit, og ud- 

 raterker sig desuden ved det eiendommelige Udseende 

 af Exopoditens dorsale Lap. Denne er nemlig paa 

 begge disse Par omformet til en cylindrisk Streng, 

 der er hageformigt omljoiet i Enden og lier for.synet 

 med en tæt Ciliering. Det er aabenbart, at disse 

 4 Appendices (se ogsaa Tab. XIX, Eig. 1, Fig. 9, fh) 

 er bestemt til. i Forening med de ovenfor omtalte, 

 fra Rygsiden af de 2 bagerste Truncus-Segmenter 

 udgaaende, bladformige Plader (1), at stotte de 2 

 kageformige Ægmasser, der bæres under Skallens 

 bagre Del. 



De 2 sidste Fodpar (Tab. XX, Fig. 4, 5) er meget 

 smaa, navnlig det bagerste (12te) Par, og mangler 

 baade Epipodit og den dorsale Lap af Exopoditen. 

 Forovrigt ligner de i Strnctnr de 2 foregaaende Par, 

 og har, som disse, alle Enditer, ligesom ogsaa Coxal- 

 lappen, tydeligt udviklede, skjoudt meget tæt sam- 

 mentrængte. Den ventrale Lap af Exopoditen er 

 paa sidste Par (Fig. 5) reduceret til et fra den ydre 

 Side af Endopoditen udgaaende meget lidet, med 5 

 Burster forsynet Appendix. 



Beskrivelse af Haiiueu. 



Hannerne er gjennemgaaende noget mindre end 

 Hnnnerne, idet Skallen neppe opnaar en Længde af 

 4 mm. Den er ogsaa (se Tab. XVIII, Fig. 3) noget 

 mere uregelmæssig af Form, med Forenden mere 

 tvært afkuttet, og de nedre Kanter dannende fortil 

 en meget stærk, næsten vinkelformig Krumning. 

 Forovrigt ligner Skallen samme hos Hunnen og er 

 fuldkommen ligesaa stærkt buget som hos denne. 



Det i Skallen indesluttede Dyr (se Tab. XX, 

 Fig. G) viser flere characteristiske Eiendommelig- 

 heder, hvorved det strax skiller sig fra samme hos 

 Hunnen. Hovedet er saaledes betydelig kortere og 

 Rostrum af en meget afvigende Form. Seet fra 

 Siden (se Tab. XVIII, Fig. 3, Tab. XX, Fig. 6) er 

 det næsten jevnt bredt og har Enden, ikke som hos 

 Hunnen udtrukket til en skarp Spids, men stumpt 

 afrundet. Forfra seet (Tab. XVIII, Fig. 5) viser det 

 sig tvært afkuttet i Enden, idet den mediane Spids 

 ganske mangler, medens de laterale Fortsatser, hvori 

 Hovedets Sidekjole gaar ud, er betydelig mere ud- 

 staaende end hos Hunnen og næsten retvinklede. 

 Af de eiendommelige trefligede Blade, der hos Hun- 

 nen udgaar fra Rj-gsiden af Truncus bagtil, er der 

 intetsomhelst Spor at opdage (se Tab. XX, Fig. 6). 



Haledelen (Fig. 10) har ogsaa en noget for.skjel- 

 lig Form, idet de 2 Endetlige er betydelig stærkere 

 forlængede end hos Hunnen og tættere cilierede. 



The 2 succeeding (9th and lOth) pairs (see fig. 3) 

 are, like the 8th, marked by a total absence of an 

 epipodite, and are also distinguished by the peculiar 

 appearance of the dorsal lobe of the exopodite. In 

 both these pairs, this lobe is converted into a 

 cylindrical cord, which is bent down at the end like 

 a hook, and thickly ciliated. It is evident that 

 these 4 appendages (see also PI. XIX, fig. 1, fig. 9, /"ft) 

 are intended, in conjunction with the above-men- 

 tioned leaf-like lamellæ (1) issuing from the dorsal 

 side of the 2 hindmost segments of the trunk, to 

 support the 2 cake-like masses of eggs, which are 

 borne beneath the posterior part of the shell. 



The last 2 pairs of legs (PL XX, figs. 4, 5) are 

 very small, especially the hindmost (12th) pair, and 

 are without both epipodite and dorsal lobe of the 

 exopodite. In other respects they resemble the 2 

 preceding pairs in structure, and have, like them, 

 aU the endites, as well as the coxal lobe, distinctly 

 developed, although very closely crowded together. 

 The ventral lobe of the exopodite in the last pair 

 (fig. 5) is reduced |to a very small appendage pro- 

 jecting from the outer side of the endopodite, and 

 furnished with h bristles. 



Description of the Male. 



The males, on an average, are rather smaller 

 than the females, as the shell scarcely attains a 

 length of 4 mm. It is also (see PI. XVIII, fig. 3) 

 rather more irregular in shape, with the anterior 

 end more abruptly truncated, and the lower edges 

 forming in front a very sharp, almost angular cm-ve. 

 In other respects the shell resembles that of the 

 female, and is quite as much vaulted. 



The animal enclosed in the shell (see PL XX, 

 fig. 6) exhibits several characteristic peculiarities, 

 thereby being immediately distinguished from the 

 female. The head is considerably shorter, and the 

 rostrum of a very different shape. Seen from the 

 side (see PL XVlil, fig. 3; PL XX, fig. 6), it is of 

 almost even breadth, the end not being drawn out, 

 as in the female, to a sharp point, but being bluntly 

 rounded. Seen from the front (PL XVIII, fig. 5), 

 it appears abruptly truncated at the end, the median 

 point being altogether absent, while the lateral pro- 

 jections into which the side keels of the head are 

 produced are considerably more prominent than in 

 the female, and almost rectangular. There is no 

 trace whatever to be discovered of the peculiar tri- 

 lobed lamellæ, which, in the female, issue from the 

 dorsal surface of the trunk behind (see PL XX, 

 fig. 6). 



The caudal part (fig. 10) is also of a somewhat 

 difi'ei'ent shape, the 2 terminal lobes being consider- 

 ably more elongated than in the female, and more 

 thickly ciliated. 



