6 DR P. P. C. HOEK ON THE 



Some of these differences may be due to variation of the species, the others 

 to the provisional character of the paper of Professor Sars. Nor would I have 

 insisted upon this disagreement had not the specimens collected with H.M.S. 

 " Triton " shown also some of the variations from the description of Sars pointed 

 out by Wilson. 



The largest specimen collected by the " Triton " measures 20 mm. ; the 

 proboscis, which is slightly swollen a little behind the middle, is not quite 

 10 mm. The abdomen, according to Sars and Wilson, is one-third the length 

 of the trunk ; in the " Triton " specimens, however, it is Only one-fourth that 

 length. The third (second, Sars) joint of the palpus is a great deal longer than 

 the fifth (fourth, Sars). The eighth joint of the palpus is globose, and much 

 shorter than the two last. The claw of the ovigerous leg is not confluent with 

 the last joint (Sars) : in my specimens, as in those of Wilson, there is a distinct 

 articulation between them. The colour of the specimens is beautiful orange. 



There are in all eight specimens. Of these five are from 16 to 20 mm., and 

 about, or quite, full grown. The three other specimens measure from 9 to 

 12 mm., and are furnished with very slender and three-jointed mandibles (fig. 8). 

 The last joint of these mandibles terminate in minute rudimentary chelae. 



I observed the same in a young male specimen of Colossendeis gracilis 

 collected during the cruise of H.M.S. " Challenger" [vide Report " Challenger " 

 Pycnogonida, p. 69). It is a very curious fact that some of the species of 

 the genus Colossendeis retain a pair of appendices of the larval state almost 

 till the animal has reached the size of the adult ; and these appendices do 

 not remain in the extremely small and feeble condition of larval life, but 

 grow with the proboscis till the length of this part of the body surpasses half 

 its length when full grown. Probably the mandibles are only lost when the 

 animal comes to maturity. 



This species is an inhabitant of the cold water area ; the highest latitude 

 at which it has been observed is 63° 10' 2" : it has not been found as yet in 

 the Arctic region. Sars obtained it from 417, the "Triton" from 466 to 640 

 fathoms. Off the eastern coast of the United States Mr Agassiz has dredged 

 it at a depth of from 810 to 1242 fathoms — a striking instance of the southward 

 extension of Arctic forms in deep water, as Mr Wilson says ; for though it has 

 not been found in the Arctic Ocean as yet, we may safely conclude, from its 

 occurrence in the cold water area, that hereafter it will be met with there. 



Seven specimens were taken at Station No. 8 and one at Station No. 6. 



10. Pallme malleolata, G. O. Sars. 



G. O. Sars, Crustacea et Pycnogonida nova, Arch, for Math, og Naturv., iv. p. 469, 1879. 



(Plate I. fig. 7.) 

 I know this species only from the description of Professor G. O. Sars. 



