156 Annals of the South African Museum. 



new family Paraleuconidas, in which the male has only one pair 

 of pleopods. In the second, for which the family Hemileuconidse is 

 proposed, the male has no pleopods, and this is the case also with 

 the Heteroleuconidas, represented by Heteroleucon, which has the 

 further character to separate it from the other three families that 

 only the first two pairs of peraeopods carry exopods in either sex. 



GEN. LEUCON, Kroyer. 



1846. Leucon (part), Kroyer, Naturhist. Tidsskrift, Ser. 2, vol. ii., 



p. 208. 

 1900. L., Sars, Crustacea of Norway, vol. Hi., p. 29. 



Carapace with longitudinal, medio-dorsal, serrate crest in female, 

 but often not in male ; pseudorostral projection prominent ; peduncle 

 of first antennae not conspicuously geniculate, accessory flagellum 

 minute ; terminal joint of second antennae in female well defined. 



The new species here introduced brings the number of species at 

 present included in this genus up to twenty. 



LEUCON KALLUKOPUS, n. sp. 

 Plate LVII. 



This species belongs to the small group in which the one-jointed 



accessory flagellum of the first antenna is not shorter than the first 



joint of the principal flagellum, and to the still smaller group in 



which the outer ramus of the uropod is much shorter than the 



inner. It makes undoubtedly a close approach to Leucon loni/i- 



rostris, Sars, taking into account the successive descriptions of that 



species by Sars in 1871, by Norman in 1879, and by Caiman in 



1906. Sars had at command a young male ending with the second 



segment of the pleon, the fragment being scarcely 4 mm. long. He 



describes the accessory flagellum of the first antenna as rudimentary 



and like a tubercle. It was taken off the coast of Portugal at a 



depth of 1,036 m. Norman's specimen, a female, was taken at the 



entrance of Davis Strait in lat. 59 10' N., at a depth of 3,109 m. 



Caiman examined specimens male, female, and young from the 



Mediterranean, taken at depths between 950 and 1,200 rn. He did 



not find among them the rudimentary accessory flagellum of the first 



antenna, but only such as matched in length the first joint of the 



principal. He gives the total length of the adult male as 6 mm., 



from which it may be inferred that the specimen described by Sars 



was at least as long when perfect, or probably longer. There is a 



