Genus Callinectes. 579 



the characters of the carapax it resembles larvatus^ but the 

 carapax is more evenly convex, and the areolations are not 

 so swollen, nor the granulations so coarse. The teeth of 

 the front are less prominent. The antero-lateral border is 

 rather more circular, and its teeth quite different from those 

 of larvatus^ being broad, convex, and close together. The 

 sternum, instead of being narrow and somewhat convex as 

 in larvatus, is broad and flat as in arcuatus. The abdomen 

 of the male bears most resemblance to that of larvatus, while 

 the intromittent organs closely resemble those of arcuatus, 

 and are very different from those of larvatus. They are 

 long, slender, and straight, as in arcuatus, though they dif- 

 fer in being slightly longer and less bent at their tips. 



The spines on the meros joint of the chelipeds are not 

 so close together as in arcuatus, and the spine at the base 

 of the manus is much longer and curved. 



This species is a small one, our largest specimen being 

 less than half the size of hastatus. 



Found at Panama by Alex. Agassiz, Esq. ' 



Remarks. 



The scanty materials that most authors have possessed 

 have prevented them from arriving at any definite and cor- 

 rect idea of the species of Callinectes, and very great con- 

 fusion has arisen on the subject. Many authors have 

 thought that there is but one species on the eastern coast, 

 and even those of the western coast have been considered 

 identical with it. Consequently the descriptions in the 

 few cases in which descriptions are given, are such that 

 it is impossible to tell to what species they allude, and 

 evidently in many instances the writers have had several 

 before them. Such being the confusion, it is difficult to 

 determine the synonymy of the different species with accu- 

 racy, so that I have reserved my opinions on that point for 

 separate consideration. 



