A REVIEW OF THE MYSIDACEA 159 



Type lot.— Two adult females, U.S.N.M. No. 81266, Albatross station 

 3697, Japan. 



Occurrence. — Japan : Albatross station 3697, 2 adult females (type 

 lot). 



Distribution. — This species was collected off the coasts of Japan in 

 120 to 264 fathoms. P. abyssi is known only from the Arctic Ocean 

 in 781 to 1,309 fathoms in water with the temperature below zero. 

 The discovery of a new species of this rare and interesting genus in 

 a new and isolated geographical area is a matter of great interest. It 

 may be noted that P. dactylops occurs in much shallower water than 

 does P. abyssi, and in correlation with this habit the eyes, while much 

 reduced, are larger and better developed than in the latter species. 



Genus MYSIDETES Holt and Tattersall 



Mysidetes Holt and Tatteksall, 1906b, p. 39. 



MYSIDETES CRASSA Hansen 



This species is recorded on page 247. 



Tribe MYSINI 



Endopods of the third to the eighth thoracic limbs with the carpus 

 and propodus' fused and the combined joint subdivided by vertical 

 articulations into a number of subjoints; first and second pleopods of 

 the male rudimentary, exopod of the fourth pair always very 

 elongated, antennal scale and telson very variable. 



Remarks. — This is the largest tribe of the Mysinae. About 31 

 genera have been referred to it, and 15 of these are represented in the 

 collections of the United States National Museum, though not all are 

 found off the American coasts. In general, the members of this tribe 

 are littoral and coastal in habit and dominate the shallow water 

 mysidacean fauna. 



Genus INUSITATOMYSIS Ii" 



Inusitatomysis Ii, 1940, p. 162. 



Antennal scale with the outer margin devoid of setae, serrate, and 

 terminating in a strong spine. 



12 At the time the manuscript for the present publication was prepared Dr. Tattersall 

 was apparently unaware of Ii's paper in which the genus Inusitatomysis was established. 

 He therefore proposed a new genus for the species described below. Although this species 

 i- obviously distinct from the genotype of Inusitatomysis, it appears to be congeneric with 

 it. Tattersall was inclined to assign the genus to the tribe Leptomysini near the genus 

 Mysidetes, stating that the "antennal scale is, however, quite unlike that of any other 

 genus of the tribe, in having the outer margin devoid of setae and serrated. The telson 

 is of a form not uncommon in other genera of this tribe and the mouth parts and thoracic 

 limbs seem to me to be more like those of the Leptomysini in general than of the Mysini." 

 These circumstances have been brought to our attention by Dr. A. H. Banner, of the 

 University of Hawaii. — F. A. Chace, Jr. 



