﻿COPKPODA loi 



male differs from the female by the presence of a fifth pair of legs which as shown in text-fig. 25 n, 

 is like that of Gaidiiis. 



Y (St. IV). Size of male from Thor St. 165 was 3-29 mm.; anterior division 2-6; urosome 

 0-69 mm. 



The body is comparatively slender, a distinct limitation between the head and the first thoracic 

 tergite is observed, the somites IV and V are as in other stages fnsed with well marked lateral spines. 

 The relative length of the abdominal somites and the fnrca is ir, 17, 19 and 13; the furcal rami 

 are 1-4 as long as wide. The aiitoiiiiilne extend al)out 3 segments beyond the end of the abdomen. 

 Tlie niaxillitlac differ as iisnal by the 9 setae of Re, but the Hasp. Ill has oni\- 3 Sa ■ 1 Sp, and the 

 Ri I — II each 2 Sa -j- i Sp; the laminons process of the ma.xillipeds has a slightly different shape with- 

 ont terminal tooth (text-fig. 25 1). The pes I has Re II — III fnsed, bnt Se Re II is present; the fonrth 

 pair of legs (fig- 3 g) has like tlie two preceding pairs, the Re II ~ III fn.sed, with 3 vSe and 16 teeth 

 in the terminal seta; the secretory pore corresponding to the Se Re II is missing. The only difference 

 between the 2 sexes is fonnd in the presence of a fifth pair of legs of the nsnal rndimenlar\- type in 

 the male (text-fig. 25 o). 



Y (St. III). Size of specimen Thor St. 167 2-48 nun.; anterior di\-ision 2^07 mm.; urosome 0-41. 

 The shape of the body is distinctly more slender, and so is the frontal spine; the rostrum is 



blunt; the head is as in preceding stage well separated fn^)m the first thoracic somite, but also the 

 fourth from the fifth one, which has no lateral spines. The relati\'c length between the two ab- 

 dominal somites and the fnrca, which is 1-4 as long as wide, is 12, 20 and 11. The aiifrinnilfjc extend 

 4 segments beyond the tip of the abdomen; the segments 2 — 3 and 4 — 5 seem to be fused, and the 

 measurements are in several respect rather different; it is cnriotrs that the segment 25, whicli is well 

 separated from the preceding one, is not only relatively but also absolutely longer than in any of tlie 

 preceding stages (it is shortest in the f$). The )iiaxilhihu- are like those of preceding stage, but differ 

 by 8 setae in the Re and by the Li I, in which one of the posterior setae is wanting (only 3 present), 

 and one of the anterior ones (S 5) is represented by a short spine. The oilier mouth appendages, except 

 tiie iiiaxillipcih which have the the laminons process romided, are in main features like those of 

 preceding stages (text-fig. m). 



The pes II, which like pes III— 1\' liave the Ri unsegniented, has a fairU' distinct limitation 

 between Re I and Re II — III, and is in main features like fig. 3g; the ]ies III differs from II by less 

 distinct limitation between Re I and Re II ~ III, bnt the latter scgmenl has onl\- 2 Se; tlie pes IV 

 is again more reduced, as seen in fig. 3 li, as all the segments are coiiipletel\' fused, ami as only a 

 single secretory pore was found. 



Variation etc. A single specimen from Thor St. 152 showed a rather curious shape of the 

 dorsal outline beliind the frontal spine; as the s])ecies was in all other respects like the rest, the 

 structure ought perhaps to be regarded as a kind of deformit}" (te.\t-fig. 25 f). 



"vSacshaped structures" like those described in (',. Icniiispiinix arc found in several specimens, 

 mostly adult females, but also in young ones of the peiiultimale stage; the following number of "para- 

 .sites" were found in sani])lcs from the fallowing 6 stations of Thor viz. '9'„ 1904 St. 152 7 parasites in 



