64 Some Crustacea of Natal 
of it then being of thread-like tenuity. Mouth-organs and limbs of 
feeble structure, though in shape the latter show much agreement 
with those of Orchomenopsis, Sars. As in that genus the palp of the 
mandible is set far back, but its first joint instead of being short is 
rather unusually long, the whole palp longer than the trunk, on which 
there is an inconspicuous molar. The branchial vesicles are pleated. 
The telson is deeply cleft. 
The generic name calls attention to the family to which the new 
genus belongs, and the prefix refers not to the smallness of the 
specimens, but to the general tenuity of their apparatus. 
MICROLYSIAS XENOKERAS, sp. nov. Plate IX. 
The seemingly unique character of the second antenne has suggested 
the specific name wenokeras from the Greek €vos, strange, and képas, 
antenna. This designation might have been appropriate for the genus, 
but was precluded by external considerations of nomenclature. 
The first side-plate of the perzeon is distally produced forward in a 
rounded lobe, the fourth is deeply excavate. The third pleon-segment 
has the lower hind angle not extended. The following segment is 
dorsally arched. The telson (as preserved) is stiffly uplifted, each of 
the blunt apices carrying a small spine, the sides also being bordered 
with five or six spinules. 
The dark eyes are more or less oval, covering much of the head as 
the animal increases in size. The first antenne are normal, with first 
joint of peduncle and first of flagellum very stout, the first of the 
accessory flagellum slender. The remarkable second antennze vary 
greatly with age and sex. In all the variations observed of the male 
the terminal joint of the peduncle is the largest, but in small specimens 
this carries a tapering flagellum shorter than the peduncle, with only 
a few indistinct joints at the slender termination. In small and large 
alike the penultimate joint of the peduncle has a tuft of sete near the 
end of its upper margin, and the last joint has this margin fringed 
with setules. In the well developed male the flagellum becomes 
slender from its commencement, with attachment to the top, instead 
of the middle, of the broad distal margin of the peduncle. The joints 
are very small, and in a flagellum about five times as long as the 
peduncle they were over 60 in number, seemingly unarmed. In a 
larger animal this length was greatly exceeded, and many of the 
