NO. 1350. NA TURA L HI8T0R Y OF THE ISOPODA—RICHA RDSON. 



41 



Fig. lo. — M.\xiLi,iPED of Symmius 



CAIIDATUS; a, ANTERIOR SIDE; 

 h, POSTERIOR SIDE. X 10. 



Fig. 14.— Opercular 

 VALVE OF Symmius 

 caudatu.s. X 10. 



the four anterior thoracic segments arc consolidated and perfectly 

 united with tlie sco-nKMits. Tliose of the fifth, sixth, and seventh seg- 

 ments are distinct and evi- 

 dent in a dorsal view. 



The abdomen is composed 

 of three distinct segments — 

 two short segments pre- 

 ceding the long and narrow 

 terminal segment. The lat- 

 eral parts of the tirst two 

 abdominal segments, as well 

 as of the seventh thoracic 

 segments, are produced into 

 acute points. The terminal 

 segment is entire, with no 

 suture lines at the base. It 

 is produced in a long and narrow extremity, rounded at the apex. 

 A))out the middle of the segment there is a slight lateral expansion on 



either side. The opercular 

 valves consist each of a single 

 piece and are produced in a long 

 and narrow extremity. 



The legs of the first pair are 

 stouter and more robust than 

 the others. Those of the last 

 pair are ver}- feeble and much 

 smaller than the preceding pairs. 

 Color white, with markings 

 of grayish brown. 



Nine specimens were col- 

 lected by the U. S. Fish Commission steamer Alhatross at Ose Zaki, 

 rlapan, at a depth of 60 to 70 fathoms. 

 Ti/pe. —Out. No. 21>081, U.S.N.M. 



Family ARCTURID.F. 



ARCTURUS HIRSUTUS, new species. 



Body densely covered and beset with spines, each of which at its 

 distal end has a circle of fine hairs radiating from it in all directions 

 in a plane at right angles to the axis of the spine, giving a ver}' 

 characteristic and unusually beautiful appearance to the body. 



The head has a nunlian excavation on the frontal mtirgin. Between 

 the eyes on the anterior portion are two long spines, the longest of 

 any on the body except the two at the posterior extremity of the 

 terminal segment of the abdomen. On the posterior portion of the 

 head in the space between the eyes are four spines of (Mjual U'ligth, 

 two on eitlun- side of the median line. On the antero-lateral portion 



Fig. 15.— Legs of Sy.mmius caudatus; a, first pair: 

 b, SECOND PAIR; c, seventh pair. X 15. 



