Hbctor F. E. Jungbrsen: Chordeuma obesum, a new Parasitic Copepod. H 



some cases I have found only one simple claw on each side, probably the inner one 

 not having been developed. 



The same appendages as in the female are present, and likewise the mandibles, 

 maxillulæ and eyes absent, The antennules (ai) are proportionally lai^er, somewhat less 

 clumsy than in the female, their terminal processes a little longer, generally curved 

 upwards and basally provided with a small spine; the lower and outer is a little 

 lai^er than the upper and inner one; a similar spine to that found in the female is 

 present on the middle of the ventral aspect of the antennule. The antennæ (aj) are 

 like those of the female; the maxillæ (mx) are both proportionally and absolutely 

 larger than in the female. The basal joint (Fig. 12, i) carries on the inner side two 

 patches of small spines and a group of similar spines arranged more sparsely around 

 a central larger one; the second joint (2) has short, oblique, arched groups of spinelets 

 on the inner side, on the outer side scattered bristles, pointing towards the terminal 

 claw; the latter (3) is on the concave side provided with a large bristle and on the 

 convex side with a few smaller ones. 



The thoracic feet (Fig. 1, p^ — p^) are unsegmented, slender, almost threadlike, 

 and pointed; they may all be simple, but often a rudiment of the inner branch (i) 

 is present on the members of second, third or fourth pair in the shape of a slender 

 papilla; it is always found in young specimens, largest shortly after their emcrging 

 from the larval cuticle (PI. II, Fig. 26, i); at that age it is present also on the first 

 pair of limbs. Hairs seem never to develop on the terminal part of the feet in 

 the male. 



The smallest males found (PI. II, Fig. 26) measure 0,36 — 0,48 mm, that is about 

 half the length of that of the smallest females observed. In the case of these small 

 males I am able to state with certainty that they quite recently have undergone 

 metamorphosis: all of them have been found together with the cast larval skin, in 

 niany cases with the tip of the tail still enclosed inside the latter. As they, however, 

 are much larger than the ruptured cuticle — generally more than twico its size — they 

 must have grown considerably after emerging from it. In no case has any other 

 cuticle than that of the larva been found together with these males, and no more 

 than in the female have later stages shown any signs of further moultings. The 

 nowly hatched males differ in scveral respects from their linal shope: the body is 

 liardly curved, the head proportionally larger, tho tail with two simple clawn; the 

 appendages are proportionally larger, and all Ih« Hich.k h lnnl.s with ili^liuctly developed 

 inner branch; furthermore in the antennules lin h.wer and outer terminal prtK'es« is 

 almost as long as the remaining part; as far as I have »een, it n»presents tho grcater 

 part of the long antennule in the larva, while only the llrst or the two lirsl hasal 

 joints of the latter are transformed into the clumsy antennule of the adult. 



