898 THE VOYAGE OF H.M.S. CHALLENGER. 



not reaching back so far as those of the first and third pairs, the peduncles about as 

 long as the inner ramus, with spines fringing the lower half of one margin, the other 

 smooth, except for an apical spine ; the outer ramus shorter than the inner, each ramus 

 having marginal spines and an apical nail (in one of the second uropods the inner 

 ramus was less elongate than in the other) ; the peduncles of the third pair much 

 shorter than the rami, apically cut into three unequal teeth ; the rami broad, lanceolate, 

 unequal, with marginal spines and some feathered setag. 



Telson longer than broad, the sides converging to form an acute apex on either side, 

 the two apices being separated by an emargination of about equal length and breadth, 

 the length being between a third and a quarter of the total length of the telson. The 

 actual apices are perhaps rounded, each carrying a sort of nail broad at the base and 

 acute at the tip. 



Lengt/i. — The specimen, in the position figured, measured, in a straight line from the 

 rostrum to the back of the third pleon-segment, very nearly half an inch. 



Locality..— Station 151, off Heard Island, February 7, 1874; lat. 52° 59' 30" S., 

 long. 73° 33' 30" E.; depth, 75 fathoms; bottom, volcanic mud. One specimen. 



Remavhs. — The specific name refers to the handsome dentation of the back and the 

 perseopods. • 



Genus Lqfystius, Kroyer, 1842. 



1842. Lafystius, Krpyer, Naturh. Tidsskr., R. 1, Bd. iv. p. 156. 



1852. Laphystius, Dana, U.S. Explor. Exped., vol. xiii. pt. ii. p. 913. 



1855. „ Liljeborg, Om Hafs Crustaceer vid Kullaberg i Skane, p. 132. 



1857. Darwinia, Spence Bate, Synopsis, Ann. and Mag. Nat. Hist., ser. 2, vol. xix. p. 9. 



1857. „ White, Popular Hist. Brit. Crust., p. 170. 



1859. Laphystius, Bruzelius, Skand. Amph. Gamm., p. 98. 



1S62. Darwiniit, Spence Bate, Brit. Mus. Catal. Amph. Crust., p. 108. 



1862. Lafystius, Spence Bate, Brit. Mus. Catal. Amph. Crust., p. 109. 



1862. Darwinia, Bate and Westwood, Brit. Sess. Crust, p. 182. 



1865. Laphystius, Lilljeborg, On the Lysianassa magellanica, p. 18. 



1870. Dermophilus i ', Beneden and Bessels, Mum. cour. Acad. Boy de Belgique, vol. xxxiv. 



1870. Laphystius, Boeck, Crust, amph. bor. et arct., p. 102. 



1873. Ichthyomyzoeus ?\pars), Hesse, Ann. d. Sci. Nat., s6r. 5, t. xvii. art. 21. 



1874. Laphystius, S. I. Smith, Invert. Animals Vineyard Sound, p. 557. 



1875. „ Schi0dte, Krebsdyrenes Sugemund, Nat. Tidsskr., B. 3, Bd. x. p. 241. 



1876. „ Boeck, De Skand. og Arkt. Amph., p. 250. 1 



1878. Darwinia, Spence Bate, Crust, in Couch's Cornish Fauna revised and added to, p. 49. 

 1886. Laphystius, Gerstaecker, Bronn's Klassen uud Ordnungen, Bd. v. Abth. ii. p. 503. 



For the definition of the genus see Note on Kr0yer, 1842 (p. 199). 



1 On p. 712 Laphystius is corrected to Lafystius. 



