690 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXIII. 



HOLOPHRYXUS GIARDI, new species. 



Body of female oblong-ovate, 17 mm. by 39 mm., without any trace 

 of segmentation. (See fig. 1.) Color uniformly light yellow. 



Head represented by a bilobed prominence, which is surrounded 

 by a wide, squarish ridge projecting anteriorly and laterally. Eyes 

 wanting. 



The thorax is wider anteriorly than posteriorly, being gradually 

 restricted posteriorly. The lateral parts are not greatly swollen. 

 There are no traces of segmentation on the dorsal surface. 



The abdomen is narrower than the thorax, and tapers to a rounded 

 extremity. There is no trace of segmentation, but a slight incision on 

 either side indicates the place of coalescence of the first segment. 



The abdomen is devoid of 

 appendages, both uropoda 

 and pleopoda being entirely 

 wanting. 



On the ventral side the 

 oral area is not contracted 

 behind. It is bounded an- 

 teriorly by the projecting 

 ridge and mouth parts, and 

 laterally by the two rows 

 of coxal plates. Situated 

 just within the two rows of 

 coxal plates are five pairs 

 of legs, surrounding the oral area. From the bases of the five pairs of 

 legs arise five pairs of incubatory plates. Only the first and fifth 

 pairs are visible, the other three pairs being hidden by the overlap- 

 ping fifth pair. The fifth pair of plates are the largest, and meet 

 along the middle ventral line of the body; they extend almost the 

 entire length of the thorax. 



In a lateral view four segments of the thorax are represented by 

 four coxal plates, bounding the outer extremity of the oral area. 

 The first coxal plate is coalesced with the cephalic ridge, but is indi- 

 cated on either side at the posterior extremity of the ridge by a little 

 pointed projection. 



One adult female was taken by the U. S. Bureau of Fisheries 

 steamer A Ibatross at Station 4793, Toporkov Island, Harbor of Nikol- 

 ski, Bering Island, north 58° east, 44 miles (54° 48' north, 164° 54' 

 east) , at a depth of 2,700 fathoms. 



Description of immature female. — The body is oblong-ovate, 3 mm. 

 by 8 mm., decreasing gradually in width from the anterior to the 

 posterior extremity. (See fig. 3.) 



a. b. c. 



FIG. 1.— HOLOPHRYXUS GIARDI. ADULT FEMALE, a. DOR 



sal view. b. Lateral view. c. Ventral view. x2|. 



