324 A HISTORY OF RECENT CRUSTACEA 
base, a single central plate issuing between the ‘ palps’ 
from the fused second joints. The marsupium is like that 
in Tanais. There are five pairs of pleopods in the male, 
and five or none in the female. The uropods have both 
branches two-jointed. 
Typhlotanais, Sars, 1880, is without eyes or ocular 
lobes. The mandibles have a thick cylindrical molar in the 
female. In the male the mouth-organs disappear as in 
Paratanais. The marsupium has the usual four pairs of 
plates. T’here are five pairs of pleopods in both sexes. 
Both branches of the uropods are two-jointed, or one or 
other of them may be one-jointed. 
Leptognathia, Sars, 1880, has no eyes or ocular lobes. 
The mandibles are weak, with a feeble pointed molar in 
the female. The mouth-organs of the male and marsu- 
pium of the female and the pleopods are as in the preced- 
ing genus. Of the uropods the inner branch is two- 
jointed in the female, three-jointed in the male, the outer 
much smaller, two- or one-jointed, sometimes rudimentary. 
Alaotanas, Norman and Stebbing, 1886, has minute 
ocular lobes, but no eyes. The mandibles are strong, with 
large molar, at least in the female, the full-grown male 
being probably content with the maxillipeds for mouth- 
organs. The marsupium and pleopods are as in the pre- 
ceding genus. The first gnathopods are powerful, espe- 
cially in the male, much like those of Leptochelia. Of the 
uropods the inner branch is eight- or nine-jointed, the 
outer two-jointed. 
Neotanais, Beddard, 1886, is no doubt the same genus 
as the preceding. Both were published by the Zoological 
Society of London in the same year. The description of 
Alaoctanais was received Noy. 5, 1884, read Dec. 2, 1884, 
and published in October 1886. Neotanais was, I believe, 
received and read considerably later, but actually published 
earlier. Mr. Beddard mentions ‘ mandibles with the usual 
structure, with a slender extremity and a stout molar 
process.’ His only specimens were males, but not perhaps 
at the stage when the mandibles would be lost.. 
Bathytanais, Beddard, 1886, has distinct ocular lobes, 
