2 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



the slight build of the small claw. Dana's species is from Rio 

 Janeiro, and the species of the Brevicarpus group (to which A. 

 minus belongs) are not as yet known to extend beyond Bahia. But 

 that is a purely negative assumption, of very little value, and I still, 

 as the most plausible explanation, consider that the antennal scale 

 was accidentally omitted from Dana's drawing. The absence of this 

 scale would suggest the L^evimanus group; but none of the species 

 of this group have the external spine of the basicerite so short or 

 the stylocerite so long. The exact identification of the form is, 

 however, imijossible because of the large number of closely related 

 sj)ecies and the slightness of the distinctive characters. 



Alpheus tni7ius is no longer represented by authentic specimens, 

 except the two dried examples, fortunately alike, preserved in the 

 British Museum and sent to Doctor Leach by Thomas Say himself. 

 They can be identified with a rather common species from Florida 

 and the Bahamas; such a determination would probably not be pos- 

 sible for all the specimens collected by Say, did they still exist. 

 Another species from the same region, appearing to be even more 

 common, is that which Herrick has described under the name of .i. 

 saulcyi hrevicarpus, in opposition to his ^1. smiley i longicarpus. Far 

 from being closely allied varieties of a single species, these tAvo forms 

 are in reality widely separated and easily distinguished ; furthermore, 

 S. hrevicarpus., which I had formerly considered synonjmious with 

 S. minus (Say), is also distinct, and each of these two species pos- 

 sesses several subspecies, forming a small, well-defined group which 

 may be designated as the Brevicarpus group, which, so far as is 

 known at present, is characteristic of the American region. 



I have not succeeded in identifying Alpheus sauleyl Guerin with 

 any of the forms which I have studied ; the species belongs obviously 

 to the Brevicarpus group, being perhaps synonymous with S. hrevi- 

 carpus (Herrick). In Guerin'S drawing the chief character which 

 recalls this species is the narrow form of the antennules; but the 

 frontal teeth, the scaphocerite, the superior prominence of the basi- 

 cerite are very imperfectly figured. As Guerin's species is from Cuba, 

 I should be more inclined to believe it synonymous with the new form 

 which I have named S. hrevicarpus guerini, which is also from the 

 West Indies, and which in other respects appears most comparable to 

 Guerin's figure. This resemblance is, however, much too vague for 

 me to consider myself justified in retaining the name of saulcyi, in 

 spite of my desire to do so. 



As to Alpheus longicarpus, I have been able to examine two speci- 

 mens received from Professor Herrick; because of the dissimilarity 

 of these two specimens, I had thought it wisest to distinguish all those 

 which corresponded to them respectively under the name of longicarpus 

 a and /?, but this distinction is veiy far from being satisfactory ; for 



