148 STALK-EYED CRUSTACEA. 
Famity PALAMONID i. 
PALAIMON Fasnr. (restr.). 
Suppl. Ent. Syst., pp. 378, 402, 1798. Restricted by Stimpson, Proc. Acad. Nat. Sci. Phila., 1860, p. 41. 
Palemon jamaicensis (Herssr). 
Cancer (Astacus) jamaicensis Herbst, Naturgesch. der Krabben und Krebse, II. 57, Plate XX VIL Fig. 2, 
1796. 
Palemon jamaicensis Olivier, Encycl. Méth., Insectes, VIII. 659, 1811. 
Six specimens from Panama, March 12. 
This well known fresh-water prawn inhabits the Atlantic coast of America 
from the West Indies and the Gulf of Mexico to Rio Sao Francisco, Brazil. 
It has been found also on the Pacific side at Polvon, Nicaragua,* and there 
are specimens in this Museum collected by Dr. Gustav Eisen, in fresh water 
near Cape St. Lucas, Lower California. 
Famity PANDALID. 
HETEROCARPUS A. M. Epw. 
Ann. Sci. Nat., 6¢™° Sér., Zool., Vol. XI., Art. 4, p. 8, 1881. 
Heterocarpus vicarius Fax. 
Pie XT, Hig.d5 A? 1s Plare Xd, Fig. 22 
Bull. Mus. Comp. Zodl., XXIV. 203, 1893. 
The rostrum is considerably shorter than the remaining portion of the 
carapace (in very small, immature individuals it is relatively much longer), 
and its distal part is turned obliquely upward ; it is armed above with seven 
or eight teeth, below with about twelve. The median dorsal line of the 
carapace is very convex and furnished with a prominent keel which is con- 
tinuous anteriorly with the superior keel of the rostrum and terminates pos- 
teriorly a short distance before attaining the posterior border of the carapace; 
this keel is armed with four or five teeth on the gastric area, back of the 
base of the rostrum. On each side of the carapace there are, in addition to 
the light marginal keel along the infero-lateral border, two prominent longi- 
tudinal ridges or carinw.} The upper one begins near the posterior margin 
* Smith, Ann. Rep. Peabody Acad. Sci. for 1869 and 1870, p. 97, 1871. 
+ The carine of the carapace play such an important part in descriptions of the species of the genus 
Heterocarpus that they deserve to be considered here in some detail. When they are developed to the fullest 
degree, we find, in addition to the median dorsal and the inferior marginal carina, three lateral carine on 
