32 
Fam. Potamonidae, 
1897. Potamonidae, Ortmann, Zool. Jahrb., Vol. X., p. 296. 
18098. Thelphustdae, de Man, Bull. Soc. Philomath. Paris, 
én 5; VOLK, p./Bbr 
1899. Telphusidae, ‘Alcock, Journ. Asiat: Soc. Bengal, Vol. 
EX VIGIL: Pt.2.4p.52: 
1900. Potamonidae, M. J. Rathbun, Proc. U.S. Mus., Vol. 
MALL, pr2s2. 
An important key to the genera and numerous species of 
this family will be found in Ortmann’s work above cited. Miss 
Rathbun gives a key to the West African species, distinguishing 
the genera Parathelphusa, Milne-Edwards,Evimetopus. Rathbun, 
and Potamon, Savigny, to which Potamonautes, McLeay, and 
Geothelphusa, Stimpson, are assigned as subgenera. De Man 
in his list of freshwater Brachyura “ de l’Inde, de la Birmanie. 
de la presquwile de Malacca et de lIndo-Chine orientale,” 
mentions five species as belonging to Potamon (Potamonautes), 
thirteen to Potamon (Potamon), and eight to Parathelphusa. . 
Gen. Potamonautes, McLeay. 
1838. Potamonautes, McLeay, in Smith’s [lustrations of the 
Zoology of South Africa, Invert., p. 64. 
1843. Thelphusa, Krauss, Siidafrik. Crustaceen, p. 37. 
1884. Potamonautes, Miers, Challenger Brachyura. Reports, 
Vol EX VEL po 2ras 
1893. Potamonautes, Ortmann, Zool. Jahrb., Vol. VII., p. 489. 
1897. Potamonautes, Ortmann. Zool. Jahrb., Vol. X, p. 303. 
McLeay, after giving “ Fam. Thelphusidae, Subgenus Thel- 
phusa Lat. Th. perlata M.-Edw. ; adds the remark, * [ separate 
those species of Thelphusa, which, like the present, have a 
transversal crest in front of the shell, and call them Potamo- 
nautes.” Ortmann divides Potamon, Savigny, into four inter- 
connected groups, to which he gives the rank of subgenera, 
naming them Potamon, Acanthothelphusa, Geothelphusa, and 
Potamonautes. The last he distinguishes as having “ lateral 
margins without spines behind the epibranchial tooth, the 
latter generally prominent; post-frontal crest continuous, 
almost straight or only at the sides slightly waved.” To this 
may be added from the earlier account by Miers that there are 
‘““ sometimes one or more lateral teeth developed in front of the 
epibranchial tooth.” 
