CRUSTACEA MALACOSTRACA. III. 209 



This interesting parasite has been extremely well worked out by the French authors and by 

 G. O. Sars. I am only able to add a little on the second larval stage, as the figures in question drawn 

 by Sars are somewhat too small. 



The antenuulse of that larval stage are extremely characteristic (fig. 14 a). The first joint of 

 the left antenuula touches that of the right at the median line in front of the mouth; the anterior 

 margin of the joint is moderately long, but shorter than that of the second; posteriorly the joint is 

 produced into a long, narrow, acute process, and the outer margin is distinctly concave without 

 armature. Second joint is large, subtriaugular, and its long distal margin has three oblong, acute pro- 

 cesses, the anterior smaller than the others, and at its base on the lower surface of the joint is found 

 a tooth. Of the two rami one is somewhat long, the other very short and distally widened. — The 

 sucking-disk is somewhat large, seen from below deeply funnel-shaped, with an area along the whole 

 margin finely sculptured. — The hand of seventh pair of thoracic legs (fig. 14 b) robust, only twice as 

 long as deep; the two lappets at the prehensile margin are well developed, and each with six branches. 



— Length ri mm. 



Sars has figured what he believed to be first larval stage of this species, and his specimens 

 were taken in Plankton samples. Perhaps his interpretation is right, but I am not quite sure, as his 

 figure shows the hands of the thoracic legs very long and slender and, what is of special importance, 

 with the thin "claw" very short. But from a marsupium I have a number of young which certainly 

 are still a little more juvenile, as each leg is still enclosed within the embryonic membrane, but through 

 this membrane the hands are seen to be somewhat thicker with the new "claw" very long, and it 

 seems somewhat improbable that the "claw" is later much reduced in length. 



Remarks. It is well known that the female with its male is found in the marsupium of 

 Mysis oculata or M. mixta. But among the large material from Hurry Inlet I found a young female 

 beneath the posterior lateral part of the carapace; the marsupium of the host is rudimentary, and the 

 parasite is scarcely more developed than the youngest female figured by Sars on PI. 94. In four spec- 

 imens of Mysis with a full-grown female in the marsupium I found a larva in second stage fixed on 

 one of the pleopods of second or third pair. 



Occurrence. Not found by the "Ingolf". 



The parasite has been taken on M. oculata from a number of stations along West Greenland, 

 viz. Murchison Sound, ab. Lat. jfip' N., 25 fath. (Ohlin); Duck Island, Lat. 73°55' N., 3-15 fath. (Ohlin); 

 Kingigtok, Lat. 7^17' N. (Ohlin); Jacobshavn, Lat. 69°i3' N. (Mag. Traustedt leg); Claushavn, Lat. 

 69°05' N., 5—10 and 10—15 fath. (H.J. Hansen); Egedesminde, Lat. 68°42' N., 20—25 fath. (Bergendal 

 leg.); Holsteensborg, Lat. 66°56' N. (Traustedt leg.), and Brede Fjord, ab. Lat. 6iV 3 ° N. (Stephensen leg.) 



— At East Greenland it is more common. At Angmagsalik, Lat. 65°3o' N., it was taken on Mysis ocu- 

 lata in 10—15 fath. by the 1st Amdrup Exp., and in 10— o fath. by the Ilnd Amdrup Exp.; in Hurry 

 Inlet, Lat. 70°5o' N., the Ilnd Amdrup Exp. secured a large number of M. oculata and some specimens 

 of M. mixta with the parasite in 7—0 fath.; furthermore at Sabine Island; Lat. 74°3o' N. (Buchholz), 

 and in Danmark Havn, Lat. 76°45' N., on M. oculata in from 0—5 to 10 fath. (Stephensen). -- Sars 

 stated it to be common on M. oculata at Jan Mayen, but it is not known from Iceland. 



Distribution. It has been taken at Norway on M. mixta at Lat. 66° N. and on M. oculata 



The Ingolf-Expedition. III. J. 2 7 



