G. M. Thomson. — On New Zealand Pycuogonida. 247 



The legs of the 3rd pair are 7'5 mm. long ; the relative lengths of the 

 joints being as follows : — 



1, 2, 3, 4, 5, 6, 7, 



4. 5. 16. 34. 32. 42. 2.' 



the 4th being much the stoutest. The 4th and 5th joints are sparingly 



furnished with hairs, the slender 6th joint has a considerable number. 



The tarsal joints and claws are normal. 



Hab. Only one specimen of this elegant species was taken in Otago 



Harbour (27 feet) by the dredge. From its small size, I am afraid it was 



immature, but the great enlargement of the 4th joints of the legs would 



show that it was not far from sexual maturity, although no eggs were seen. 



Genus II. Phoxichilidium, Milne.-Edwards. 



Body usually cylindrical, sometimes contracted and disc-like. Proboscis 

 always strong, cylindrical, directed forwards ; usually inserted considerably 

 behind the insertion of the mandibles. Mandibles 3- (? 2-) jointed, the 

 last joint with movable claws bent down in front of the mouth. Palpi 

 wanting ; represented by a small tubercle on the wall of the anterior seg- 

 ment. Ovigerous legs 5-10-jointed, the last four joints never furnished with 

 denticulate spines ; (5-7-jointed, only present in the males, Dohm). Legs 

 having all the joints of normal length ; tarsal joint strongly spined on its 

 inner (lower) margin ; claws long, subsidiary claws rudimentary or wanting. 



The male genital openings occur in the 2nd joint of the 3rd and 4th 

 pairs of legs. 



The animals of this genus are distinguished from all other Pycnogonida 

 by a peculiar mode of development. The young, immediately on emerging 

 from the egg — at which stage they possess an obtuse pyriform body, with 

 3 pairs of rudimentary appendages — creep into the cavity of the body of a 

 hydroid polyp (Hydractinia, Coryne, etc.) and undergo the rest of their 

 development in this retreat. 



7. Phoxichilidium obliquum, n. sp. PI. xv., fig. 6 ; pi. xvi., figs. 1 and 2. 



Body contracted, lateral processes hardly separated ; the dorsal portion 

 somewhat elevated ; length 5 mm. The proboscis is very stout and cylin- 

 drical, and is directed downwards at an oblique angle ; its length is about 

 half that of the body. 



The abdomen is about 3 mm. long, and stands rather obliquely upwards 

 from the body ; it is abruptly truncated at the end, but bears two long 

 spines at the anterior side of its apex. 



The front portion of the cephalo-thoracic segment is elevated into a 

 transversely oval hump or cushion on which the oculiferous tubercle is 

 placed. This organ is prominently developed, and runs up on its anterior 

 face to a tolerably acute point ; its summit is crowned with numerous short 

 spines. 



