304 A HISTORY OF RECENT CRUSTACEA 
second pair of perzeopods spinose, with the third joint not 
defined ; the fourth pair in the female without any rudi- 
ment of the exopods. Vaunthompsonia cristata, Spence 
Bate, is British. The only other species, Vaunthompsonia 
meridionalis, Sars, is from Kerguelen. Vaunthompsonia 
anomala, Sars, is supposed by its author to represent in 
all probability another distinct genus. 
Leptocima, Sars, 1873, has the body elongate and 
much compressed, the eye indistinct, the third joint in the 
second pereopods defined, and the fourth perzeopods in 
the female with rudimentary exopods. The single species 
is Leptocuma Kinbergii, Sars, taken off the mouth of the 
Rio de la Plata. 
Heterocima, Miers, 1879, has the eye well developed, 
and the second joint of the third maxillipeds produced. 
It has the single species Heterocuma Sarsii, Miers, with a 
variety, granulata. 
Family 3.—Leuconide. 
The form is generally slender with elongate pleon. The 
eye is wanting. The first antenna have one of the flagella 
small, one-jointed. The anterior branch of the mandibles 
is without the usual series of spines, the molar tubercle 
is massive. The ‘palp’ of the first maxilla has a single 
terminal seta. The epipod of the first maxillipeds has few, 
finger-like branchial sacs. The third maxillipeds are 
rather short, with some strong setz on the outer margin. 
The first three pairs of pereopods in the female and the 
first four in the male have well-developed swimming- 
branches. The second pair of perzeopods are only six- 
jointed. There are only two pairs of pleopods in the male. 
The inner branch of the uropods is two-jointed, spinose, 
the outer being setose. The telson is wanting. 
The family contains three genera. 
Leucon, Kroyer, 1846, has the body slender, the pseudo- 
rostral projection distinctly prominent, and the 
first antenne not geniculate. There are eleven 
species known, of which the oldest Leucon nasica, 
Kroyer, has been recorded from British waters. 
