120 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Genus ORTMANNIA, nom. nov.' 
Atyoida Ort.mann, Proc. Acad. Nat. Sc.i. Phila. 1894, 406. (Not Atyoida Randall.) 
Differs from Atya chiefly in the character of the cheke of the first and second pairs of legs; the 
dactylus is inserted on the upper margin of the propodus and is shorter than the latter, forming a chela 
consisting of a palmar portion and two fingers, as is usual in the Decapoda. 
Ortmannia potimirim (F. Muller). 
Atyoida potimirim F. Muller, Kosmos, ix, 117, figs. 1-20, 1881; Arch. Mus. Nae. Riode Janeiro, vm, 155, pis. ix and x, 1892. 
Ort.mann, Proc. Acad. Nat. Sci. Phila. 1894, 407; Rev. Mus. Paulista, ir, 183, pi. i, figs. 1-3, 1897. 
Rostrum shorter than antennular peduncle, narrow, acute, having a superior unarmed median 
c-arina, and two or three teeth below. Carapace smooth; anterior margin furnished with suborbital 
spine; also a branch iostegal spine in the female, none in male. Feet all slender, those of the second 
pair reaching the end of the antennular peduncle. Carpus of second pair nearly as long as its pro- 
podus and much longer than carpus of first pair. Meral joints of third, fourth ; and fifth pairs armed 
with a few spines below, the propodi and dactvli have many smaller and more slender spines. 
Length, from 15 mm. in the male to 25 mm. in the female, according to Muller. 
Vieques Island in small stream (Dr. L. Stejneger, coll.) ; 1 male. 
Hitherto known only from Brazil, where it has been taken in the Itajahy River and at Sao 
Sebastiao in the sea. 
Family PONTON 1 1 1 ) £ Kingsley, 1878 (Pontoninse) ; Bate, 1888. 
Body often depressed; rostrum often short, compressed or depressed with or without dentations. 
Outer flagellum of first antenna consisting of a thick hairy part, bearing a thin hairless part, the latter 
usually arising from the former at a short distance from the free end, and thus giving it a bifid 
appearance. Mandible deeply cleft into two divisions and without a palp; endopodite of the second 
maxilliped not biramous; third maxilliped pediform, but usually with some of the joints broadened. 
All the legs without exopodites or mastigobranchs; first two pairs of legs chelate, first pair slender; 
second pair larger than first, not foliaceous. Mode of life often semiparasitic. (Borradaile. ) 
Key to the Porto Rican genera of the family Pontoniidse. 
A. Dactyli of last three pairs of legs slender, nearly straight, without basal protuberance Periclimenes 
A'. Dactyli of last three pairs of legs short, curved, with a basal protuberance. 
B. Antennal scale long Coralliocaris 
B'. Antennal scale short Pontonia 
1 The National Museum has lately received from Mr. H. W. Henshaw, Hilo, Hawaii, two species of river shrimp 
belonging to the family Atyidie. One is a true Atya , the other belongs to the genus Atyoida as defined by Ortmann (Proc. 
Acad. Nat. Sci. Phila. 1894,406). Either corresponds to Randall’s brief description of Atyoida bisulcata. Randall, however 
(Jour. Acad. Nat. Sci. Phila., vm. 1839, 140), says that Atyoida is essentially similar to the genus Atya, “excepting the third 
pair of feet”; this would seem to imply that the first two pairs of feet are similar to those of Atya, which is not the case in 
Atyoida as defined by Ortmann. 
Through the courtesy of Mr. Witmer Stone, of the Academy of Sciences of Philadelphia, I have been able to examine 
a dried fragment (all that remains) of Randall’s type of Atyoida bisulcata. It comprises a carapace and a foot of both the 
first and second pairs. These are without doubt feet of typical Atya, and the species is seemingly identical with one of 
those received from Mr. Henshaw; it is that figured by Dana and by Bate. The genus Atyoida Randall is therefore a 
synonym of Atya Leach. In Atya (to quote Dr. Ortmann) the “ dactylus [of the chelse] articulates with the propodus on 
the posterior end of the latter, both joints being exactly alike and forming a hand of a very peculiar shape among the 
Decapoda, the palmar portion being wholly reduced, and the hand consisting only of two fingers about alike in size 
and connected with each other at the posterior ends.” 
In the genus Atyoida Ortmann (non Randall ) for which I propose the name Ortmannia, “ the hands are formed like 
those of Caridina, the dactylus is inserted on the upper margin of the propodus, being shorter than the latter and forming a 
chela, as usual in the Decapoda, consisting of a palmar portion and two fingers.” The type is Ortmannia henshawi nom. 
nov. ( = Atyoida bisulcata Ortmann, 1894. not Randal \ = Atya bisulcata Sharp, 1893, in part, Cat. No. 162), from Kaiwiki, 
Hilo, Hawaii, 1,800 feet altitude, 3 miles from the sea, H. W. Henshaw, collector (U. S. Nat. Mus., Cat. No. 24825). 
