33 
Potamonautes perlatus (Milne-Edwards). 
1837. Thelpheusa perlata, Milne-Edwards, Hist. Nat. Crust., 
Vol ais pea 
1838. Potamonautes perlata, McLeay, Invert. Zool. S. Africa, 
p. 64. 
1843. Thelphusa perlata, Krauss, Siidafrik. Crustaceen, p. 37. 
1886. Thelphusa (Potamonautes) perlata, Miers, Challenger 
Brachyura, Reports, Vol. XVII., p. 215. 
1893. Telphusa (Potamonautes) perlata, Ortmann, Zool. Jahrb., 
Vol. VII., p. 489. 
1897. Potamon (Potamonautes) perlatum, Ortmann, Zool., 
jabrb.; Vor. X.,,ps 303. 
Many other references are supplied by Ortmann. Milne- 
Edwards, who spells the generic name indifferently Thelpheusa 
and Thelphusa, was not the first naturalist to use ferlatus, 
which properly means “carried through,” in the barbarous 
sense of “pearly.” In this species the pearls, though very 
numerous, are excessively small. They are discernible on 
the orbital margin, the mesially-notched post-frontal ridge, 
the curved line of the antero-lateral borders, dispersed over 
the pterygostomiam regions, and lining the upper edges of 
the endostome. In the chelipeds. they run along the two 
under edges of the fourth joint, and appear on the corresponding 
ridges in the second pair of legs, but seem to be obsolete in 
the three following pairs. On the other hand this joint in all 
the ambulatory legs has a pearly upper ridge, which is continued 
on to the next joint, where it is flanked by two other ridges 
in the second and third pairs, but only by a single ridge in the 
fourth and fifth pairs. The two terminal joints are grooved 
above. The chelipeds have many little transverse rows of 
granules on the upper surface of the fourth and fifth joints, 
and the seemingly smooth surface of the hand is found under 
a lens to be similarly diversified. The thumb and finger are 
long, with very unequal teeth along their confronting margins. 
A specimen labelled as coming from “* East London shore ” 
has the carapace 24mm. long, with the greatest breadth 
30°75 mm. 
Another specimen, like the preceding, a male, labelled as 
coming from “ Princess Vlei (fresh water), near Cape Town,” 
has the carapace 29 mm. long, by 39mm. broad. In this 
larger specimen the “ perlation’”’ on the underside of the 
carapace is considerably more distinct. There was no other 
tangible difference between the specimens. 
