48 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



Localities — Continued : 



Porto Rico (form antillensis) : 

 Playa cle Ponce, Fish Hawk. 



Humacao, 9i fathoms, Fish Haivk Station No. 6099. 

 Bermudas (specimen with basicerite very spinous), G. B. Goode. 

 Brazil, Plataforma, Bahia (type of form bahiensis) , R. Rathbun, 

 Hartt Explorations. 



Type of jS. minus hahiensis.— Cat No. 38396, U.S.N.M. 

 Type of S. minus antillensis.— Cnt. No. 38397, U.S.N.M. 



SYNALPHEUS DIGUETI, new species. 



This species represents the Brevicarpus group on the coast of 

 Lower California, where it has not previously been found. It is, 

 consequently, a very important extension of the geographic distribu- 

 tion of this group, which thereby ceases to be an exception from the 

 general rule. Just as the L^vimanus group possesses at least one 

 Indo-Pacific species, it will also be found that the Brevicarpus group 

 has met in that region of the globe conditions inducing specific dif- 

 ferentiation. 



S. diguetl is very near S. minus (Say) ; the differentiation is diffi- 

 cult except between adult specimens, and the more mature, the easier 

 is the determination. The characters of the males are more decided 

 than are those of the females. In the males the differences between 

 S. diguetl and S. minus are the following: (1) The antennule is 6 

 times longer than wide instead of 5 times, as in the males of corre- 

 sponding size of S. minus; (2) the carpocerite is 3.5 times longer 

 than wide instead of 3.7 times, and the lateral spine of the scapho- 

 cerite is a little shorter than the antennule; (3) the meropodite of 

 the third pair of feet is 3.5 times longer than wide instead of 3.75 

 times. 



In the females the antennule is not more than 5.8 times as long as 

 wide, and the spine of the scaphocerite slightly exceeds the antennule, 

 so that the tangible differences from the females of S. minus become 

 almost none. However, the carpocerite is somewhat thicker, 3.54 to 

 3.58 times longer than wide, while this proportion reaches 3.7 to 3.75 

 in the females of S. minus; there is also a very slight difference in the 

 thickness of the meropodite of the third pair, where the proportions 

 are nearly 3.5 in S. minus and 3.3 in S. digueti. 



There is also in both sexes a slight difference in the meropodite of 

 the small cheliped ; this is at the most as wide as the palm, and gen- 

 erally a little narrower in S. minus (proportion 0.92 to 0.96) ; in S. 

 diguetl, on the other hand, it is wider (proportion 1.1 to 1.13). 



The specimens which have just been considered do not exceed 

 25 mm. in length; in one large female measuring 30 mm. (also col- 

 lected by M. Diguet) the characters are much more clearly indicated, 



1 



