PALAEMON ROSENBERGII. 167 



the contrary, there are 10 or 11 teeth on the posterior 

 convex part of the rostrum , the two posterior teeth of which 

 being always placed behind the eyes. 



The Palaemon Lamarrei of De Haan (non Milne Edw.) 

 is therefore identical with Palaemon Amazonicus Heller. This 

 fact is the more inexplicable , because I have found the 

 Suriname specimens of Palaemon Amazonicus Heller provi- 

 ded with the name of Palaemon Dieperinkii De Haan ; 

 so that I may conclude that the latter name has been given 

 by de Haan to the American species This name, howe- 

 ver which has never been published , should disappear from 

 science and the species should henceforth bear the name 

 of Palaemon Amazonicus Heller. But is seems to me 

 very necessary that new researches confirm this pretended 

 appearance of Pal. Amazonicus in Japan ! 



Palaemon Rosenhergii n. sp. 



Length of the adult female 250 mm.; male unknown. — 

 Rostrum slender , nowhere enlarged , reaching to the extre- 

 mity of the scale of the external antennae; upper margin 

 almost straight, not convex as in Pal. carcinus Fabr., 

 curved upward a little toward apex , provided with 13 teeth, 

 the nine posterior of which being equidistant and separated 

 by a somewhat greater interval from the four anterior 

 which extend to the apex ; the three posterior teeth are 

 placed upon the cephalothorax behind the eyes ; lower 

 margin with 10 strong equidistant teeth. Cephalothorax 

 smooth ; terminal segment of the abdomen not slender and 

 acuminate as in Palaemon carcinus Fabr., but somewhat 

 rounded at the end, its lateral margins converging in a 

 much less degree than in the latter species. For the rest this 

 form closely agrees with Pal. carcinus Fabr. — The first 

 pair of legs project with half of the carpopodite beyond 

 the scale of the external antennae , the carpopodite being 

 longer than the arm and a little more than twice as lonj? 



IS^otes from the Ley den IMuseuixi. 



