no. 1691. SCITIZOPODS FROM ALASKA— ORTM. I NN 



r. Telson more or less triangular, apex truncate or cleft. Terminal 

 joint of outer branch of fourth pleopod of male with a single 

 stout terminal spine. Antenna 1 scale lanceolate or ovate. 

 f. Outer branch of fourth pleopod of male projecting only with the 

 terminal spine beyond inner branch; distal joints not at all in- 

 creasing in length. Telson triangular, apex truncate or cleft. 



Mysidopsis Sars." 

 f. Outer branch of fourth pleopod of male distinctly projecting be- 

 yond the inner, distal joints slowly increasing in length. Tel- 

 son triangular, apex with a short cleft Mysideis Sars. 6 



d 2 . Outer margin of antennal scale not setose, ending in a spine near the 

 distal end. Terminal joints of inner branch of fourth pleopod of 

 male increasing in length, especially the last one greatly elongate, 

 and bearing a spine at its end. Telson elongated-triangular, apex 



truncate, not cleft Holmesiella, new genus. 



r. Fleopods of female biramous, although rudimentary. Outer branch of 

 third pleopod of male much elongated. Outer margin of antennal scale 

 not setose, with terminal spine. Telson subrectangular, 2-3 times as 

 long as wide, outer margin spinous, spines remote proximally, but more 

 close set distally ; apex slightly emarginated, emargination spinous. 



Callomysis Holmes. 



Genus HOLMESIELLA Ortmann, new genus. d 



Diagnosis. — A genus of Mysidae, belonging to the subfamily Lep- 

 tomysinae. Body of the usual form. Eyes large. Third joint of 

 peduncle of antennulae in the male with a strong conical process on 

 the lower side of the distal extremity. Legs slightly setose, with the 

 propodite triarticulate, dactylopodite short, with a long, curved, termi- 

 nal spine. Marsupial pouch of female consisting of three pairs of 

 leaflets, the anterior small. Pleopods of female all rudimentary, short 

 and simple. Pleopods of the male all biramous, but in the first pair 

 the inner branch is short and simple ; in the second, third, and fifth pair 

 both branches are well developed, of about the same length, and mul- 

 tiarticulate ; in the fourth pair it is the inner branch that is much 

 elongated, about twice as long as the outer. The terminal joints in- 

 crease in length, and especially the last one is much elongated, almost 

 three times as long as the penultimate, and carries at the distal ex- 

 tremity a long and strong spine. The three last joints do not possess 

 any setae. Telson elongated, triangular, apex truncated, margins 

 spinulose. Uropods narrow; otolithe well developed. 



a Sars, Monogr. Mysid., II, 1872, p. 12; Norman, Ann. Nat. Hist. (6), X, 1S92, 

 p. 163. 



b Sars, Idem, III, 1879, p; 1. 



c Holmes, Proc. California Acad. Sei. (2), IV, 1895, p. 582. 



ã Named in honor of Prof. S. J. Holmes, in recognition of his work on Pacific 

 Crustaceans. 



