546 PROCEEDINGS OF THE NATIONAL MUSEU3L vol.x.xih. 



47. ARCTURUS Latreille. 



ANALYTICAL KEY TO THE SPKflES OP" ARCTrKrw. 



a. Terminal segment of abdomen armed with a lony median terminal si)ine, i)rojec't- 

 ing beyond the end of the segment. 

 b. Head with two sjiines. Second joint of second jiair of antennse armed with one 

 spine at npper end. Thorax Avith few spines. Surface of terminal abdomi- 

 nal segment smooth. 

 c. Second joint of peduncle of second pair of antennae without spine at base on 

 outer margin. First pair of antennye extending one-third the length of the 

 third joint of second pair of antennae. Dorsal spines wanting on second 

 abdominal segment. Spines w^anting on opercular valves. Anterior tho- 

 racic appendages furnished with a number of spines on the proximal joints. 



114. Arctiiruff purpureus Beddard. 

 &. Second joint of peduncle of second pair of antenna> with spine at base on 

 outer margin. First pair of antenna? extending two-thirds the length of the 

 third joint of second pair of antenna>. Dorsal spines present on second 

 abdominal segment. Spines present on opercular valves. Anterior tho- 

 racic appendages without spines except on penultimate joint. 



115. Arctiirus caribb.rus, new species. 

 y. Head with eight spines. Second joint of second pair of antennse armed with 

 three spines at the upper end. Thorax with many spines. Surface of ter- 

 minal abdominal segment with three rows of spines on dorsal surface. Row 



of spines on each opercular valve 116. Arrtiirusfloridamts Richardson. 



o/. Terminal segment of abdomen not armed with a long median terminal sjjine. 

 b. Four anterior segments of thorax with spines or tul)ercles. Middle surface of 

 abdomen with prominent spiny projections. With conical lateral projec- 

 tions. Epimera pointed 117. Airiurus baffini (Sabine). 



¥. Four anterior segments of thorax without spines or tubercles. Middle surface 

 of abdomen without any indication of prominent spiny projections. With- 

 out conical lateral projections. Epimera less pointed. 



118. Arcturus feildcni Miers. 



114. ARCTURUS PURPUREUS Beddard. 



Arcturus iturpnrem Beddard, Proc. Zool. Soc. Lond., 1886, Pt. 1, j). 109; Report 

 on the Scientific Results of the Exploring Voyage of H. M. S. Challeiujer, 

 Zool. XVII, pp. 112, 113. 



Ilah/'tat. — Off Sombrero Island. 

 Depth. — 450 fathoms. 



115. ARCTURUS CARIBB/EUS, new species. 



Head with a deep excavation on the anterior maroin, on either side 

 of which the antero-lateral margins are produced, each bearing- a short 

 spine at the outer angle. Two long spines are situated on the ante- 

 rior portion of the head, between the eyes. The tirst pair of antennte, 

 consisting of four joints, reach two-thirds of the length of the third 

 joint of the second pair of antenna?. The lirst joint of the set-ond 

 pair of antenna is short and unarmed; the second joint is armed 

 with a small spine at the base on the outer margin, and a large spine 



