PYCNOGONIDA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 161 



Between the two sexes they exhibit considerable differences. The type specimens are 

 males, and the specimen now under examination is an adult female. 



All the joints are small ; the first is short and stout ; the second, fourth, and fifth are 

 subequal, and, by a little, the longest joints of the appendage ; the third is about two- 

 thirds the size of these ; the sixth is a little shorter than the preceding ; the seventh 

 and eighth are a little shorter still and subequal ; the ninth is the shortest of all, except 

 the first ; and the tenth is slender, rather tapering, and half as long again as the ninth. 

 Setae are very scarce throughout, except on the sixth joint, where they are fairly 

 numerous though minute. The last four joints bear numerous denticulate spines, which 

 are not, however, arranged in a single row. These are unfortunately much worn, but 

 show a stout, usually curved shaft, bent, with some eight or nine very closely set teeth 

 on each side. There is no terminal claw. 



The Legs extend to a length of about 27 mm. Of the three coxae, the first is the 

 shortest, the second is rather more than twice as long, and the third is intermediate 

 between the two. The proportions of the three following joints are as 6, 5, 7, but they 

 are not strictly preserved on all the legs. The tarsus is very small, covered with stiff 

 setae, which become distinctly spinous as a ventral distal fringe. The propodus is rather 

 curved ; ventrally and proximally there is a row of very stout spines, five in number. The 

 rest of the joint is thickly covered with short stiff setae, especially ventrally ; dorsally 

 there are a few longer ones. The heel does not project much and is fringed with stiff 

 setae. The terminal claw is long and stout, with two large auxiliaries more than half as 

 long ; the three rise from a common membranous investment. 



The limb is covered fairly plentifully with short stiff setae, and there are rows on the 

 principal joints of stout spinous setae dorsally and laterally ; these are, however, not 

 closely set. The distal fringes are not conspicuous. 



The Genital apertures are found on the second coxae of all the legs. 



A single specimen was found among an enormous number of Chsetonymphon 

 orcadense taken in Scotia Bay, at 9 fathoms. 



Through the courtesy of Dr PFEPFER of Hamburg, I have been able to compare 

 this specimen with the types of his Ammothea Clausi. Though Dr PFEFFER'S 

 specimens are both ovigerous males, there cannot be any question as to the identity of 

 this specimen with that species. The ova are small and numerous, massed together in 

 two spherical packets on each oviger. 



Decolopoda australis (Plate III., figs. 2, la, 2b, 2c). 



Decolopoda australis, Eights, (8), pp. 203-206; Stebbing, (29), pp. 185-189; Cole, (6), pp. 405-415; 



Loman, (19), p. 722. 

 Decalopoda australis, Hodgson, (11), pp. 36-42; (12), pp. 254-256; Bouvier, (3), pp. 1-5. 



This fine species was discovered in some numbers along the shores of the South 

 Shetland Islands, and a very full description was published by Dr EIGHTS in the first 



(ROY. soc. EDIN. TRANS., VOL. XLVI., 181.) 



