NO. 1659. AMERICAN SPECIES OF SYNALPITEUS—COUTIERE. 



39 



tinct and spinous, is relatively easy; but in S. nilandensis oxyceros 

 these last differences have entirely disappeared, the only ones per- 

 sisting being the greater length of the supraorbital spines, that of 

 the lateral spine of the basicerite, and lastly the presence of a row of 

 five spines on the meropodite. 



A large female specimen from the Bermudas of S. hempMlU longi- 

 rornis is particularly interesting in this regard; the meropodite of 

 the left foot of the third pair bears a well developed spine; the rest 

 of the series is wanting; the opposite member is quite unarmed, but 

 the suggestion arising from this circumstance is none the less in- 

 structive, as it shows to what degree the parallelism between the 

 Indo-Pacific and the American forms may be carried. The "oa;^- 

 cei'os " forms of the species S. nilandensis and S. hemph'dU appar- 

 ently represent the first evidences of divergence of certain species 

 originally common to two regions; judging by the much greater num- 

 ber of species in the Indo- 

 Pacific region, and also 

 from the fact that there 

 only are found the forms 

 with spinulous meropo- 

 dites, one might infer 

 that that region was the 

 center of dispersion of 

 the group. 



S. faraneo'tneris Cou- 

 tiere possesses the same 

 form of hook as 8. fritz- 

 miiUeri, from which it is 

 most readily separated 

 by having the basicerite not spinous above; on the other hand, S. 

 paraneomeris is no less closely related to S. toivnsendi Coutiere, the 

 basicerite of which is unarmed above, but the dactyls of which have 

 no ventral supernumerary prominence; so that the two groups, the 

 Neomeris group and the Paulsoni group, have in these three species 

 a very evident point of approximation. 



Named for Mr. Henry Hemphill, Avho has added largely to the 

 Alpheidae in the U. S. National Museum. 



Localities : 



West coast of Florida, 21 to 28 fathoms : Albatross Station No. 

 2409, 2 specimens, type: Fish TIaivl' Station No. 7123, 1 speci- 

 men; Fish Ilawh Station No. 7124, 1 specimen (type of longi- 

 cornis.) 

 Bermudas, G. B. Goode, 2 specimens {longicornis.) 

 Type of S. hemphiUi.— Cut No. 9817, U.S.N.M. 

 Type of S. hemphilli longicornis.— C^i. No. 38395, U.S.N.M. 



Fig. 21. — Synalpheus hemphilli longicornis. a, 



FRONTAL AND ANTENNAL REGION ; m' , EXTREMITY OF 

 THIRD FOOT. 



