148 STALK-EYED CRUSTACEA. 



Family PALJEMONID^. 



PAL^MON Fabk. (restr.). 

 Suppl. Eut. Sjst., pp. 378, 402, 179S. llestiicted by Siimpson, Proc. Acad. Nat. Sci. Pliila., 1860, p. 41. 



Palsemon jamaicensis (Herbst). 



Cancer (^Astacas) Jamaicensis Herbst, Naturgcsch. der Krabbeu und Krebse, II. 57, Plate XXVII. Fig. 2, 



1796. 

 PaliBmon jamaicensis Olivier, Eacycl. Meth., Insectes, VIII. 659, 1811. 



Six specimens from Panama, March 12. 



Tliis 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. 



Family FANDALID^. 



HETEROCARPUS A. M. Edw. 



Ann. Sci. Nat., C^™" Ser., Zool., Vol. XL, Art. 4, p. 8, 1881. 



Heterocarpus vicarius Fax. 

 Plate XL., Fig. 1, T 1" ; Plate XLI., Fig. 2, ^. 



Bull. Mus. Comp. Zool., XXIV. 203, 1S93. 



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 carinas.! The upper one begins near the posterior margin 



• Smith, Ann. Rep. Pcabody Acad. Sci. for 1809 and 1870, p. 97, 1S71. 



t The carina; of the carapace play such an important jiart in descriptions of the species of the genus 

 Heterocarpus that they deserve to be considered here in some detail. When tlioy are developed to the fullest 

 dcgreft, we find, in addition to the median dorsal and the inferior marginal carina, three lateral cariuse on 



