390 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



extreme lateral margin. The first pair of antennas have the basal article 

 not enlarged; the second article is about equal in length to the first; the 

 third and fourth are subequal, and each is a little longer than the second. 

 The first antennae extend to the middle of the third peduncular article of 

 the second pair of antenme. The basal article of the second antenna? 

 is scarce^ conspicuous from a dorsal view; the second, third, and 

 fourth articles are about equal in length; the fifth is one and a half 

 times longer than the fourth. The flagellum consists of ten articles. 

 When retracted the second antennae extend to the middle of the third 

 thoracic segment. The maxillipeds have a palp of three articles. 



The first four segments of the thorax are about equal in length, and 

 each is longer than any of the last three. The epimera are all entirely 

 coalesced with the segments. The lateral portions of all the segments 

 are expanded in rounded processes. 



The terminal segment of the body or abdomen is acutely pointed at 

 the extremity. On either side at the base of the segment is a lateral 

 suture indicative of another partly coalesced segment. 



The legs are more or less similar in structure. 



SYNIDOTEA MURICATA (Harford). 



Idotea muricata HARFORD, Proc. Cal. Acad. Sci., VII, 1877, Pt. 1, p. 117. 



Synidotea muricata BENEDICT, Proc. Acad. Nat. Sci. Phila., 1897, p. 400. RICH- 

 ARDSON, Proc. U. S. Nat. Mus., XXI, 1899, p. 849; Ann. Mag. Nat. Hist. (7), 

 IV, 1899, p. 269; American Naturalist, XXXIV, 1900, p. 228. 



Locality. Icy Cape, latitude 70 U 15' 

 north, longitude 162 55' west; latitude 

 41 3' north, longitude 154 15' west. 



Depth. 25 fathoms. 



Body ovate, nearly three times longer 

 than wide, 8 mm. : 22 mm. Length of 

 abdomen a little more than one-third 

 the length of the entire body, 8 mm.: 

 22 mm. 



Head with a deep median excavation 

 or notch. Between the eyes on the 

 anterior portion of the head is a group 

 of four small but very pronounced and 

 clearly defined tubercles, two in longi- 

 tudinal series and one on either side of 

 these in transverse line half way be- 

 tween the other two. In front of the 

 eyes and a little lateral to this group 

 of tubercles are two very large tuber- 

 cles, one on either side. Just back of the group of four tubercles are 

 two groups of low tubercles, irregularly arranged in masses, one group 

 placed on either side of the median line. Posterior to these masses of 



FIG. 433. SYNIDOTEA MURICATA (AFTER 

 BENEDICT), x 21. 



