276 A HISTORY OF RECENT CRUSTACEA 
Huchetoméra, with twa species typica and tenuis from 
the Pacific, agrees with rythrops in the form of the very 
short, lamellar, unincised telson. The scale of the second 
antenna is smooth on the outer margin. The legs are 
very slender. Some of the joints of the legs, the pleopods 
in both sexes, and the uropods, are fringed with long sete, 
from which circumstance it may be supposed that the 
generic naine is derived, meaning ‘ with the parts beauti- 
fully hairy.’ Professor Chun comments on the astonishing 
length of the upper antennze in the type species, which 
he regards as a transitional form between Mysis and his 
own Arachnomysis Leuckartit. . 
Siriella, Dana, was originally named Cynthia, by 
Vaughan Thompson, but the name was preoccupied, and 
Dana’s Siriella takes precedence of White’s Cynthilia. The 
genus is characterised chiefly by the structure of the legs, 
‘which are more decidedly unguiculate than in any other 
known genus of Mysidans,’ and have the sixth joint entire 
or subdivided into two articulations only ; also by the pleo- 
pods of the male, which are natatory, and have the ‘ basal 
lobe of inner branch usually transformed into two gill-like, 
more or less spirally twisted stems.’ The outer branch of 
the uropods is broader than the inner, and has an imperfect 
articulation at the apex. ‘The telson is elongate, densely 
spinose at the edges, with the apex not incised. The 
species are numerous, and many of them are met with at 
the surface of the sea, far from the coast. The British 
species, as far as at present known, are: 1. Siriella norve- 
guca, Sars, in which the third joint of the first antenne has 
three setze on the inner margin, and between the spines 
at the angles of the telson three spinules, of which the 
central is the largest. 2. Siriella Clausii, Sars, of which 
Norman gives the distinguishing characters as ‘ the single 
seta on inner margin of last joint of peduncle of antennules, 
the slender legs and claws, and three equal-sized spinules 
between the ultimate spines of the telson.’ 3. Siriella 
jaltensis, Czerniaysky, identified by Norman with the later 
Siriella crassipes, Sars, in which the form is somewhat 
more robust and the legs much stronger than in the 
