smooth, body not greatly compressed. Epimera of second segment overlap- 
ping those of preceding and succeeding segments. 
Flagella of inner antenne about half as long as body, those of outer antenne 
more than three-quarters as long as body. 
Hands of first pair of legs dissimilar both in size and form. Fingers of 
smaller pair straight, parallel and slender, closely fitting; the manus with a 
spine above, and a constriction posterior to the insertion of the dactylos. 
Manus of larger or right hand large, with a large spine on the outer side, 
continued as a carina fora considerable distance backwards, and with a deep 
sulcus above the carina. Dactylos short, curved obliquely downwards, thick 
and swollen at the extremity. A deep transverse sulcus between the dactylos 
and manus, ending in an oblique longitudinal sulcus having its origin on the 
upper edge of the manus; from the latter sulcus a second transverse one is 
continued down the inner side of the manus. 
Both hands setose, the hairs long and numerous. 
Carpus of second pair five-jointed, third and fourth joints shortest, the 
manus and dactylos slender. 
Leneth, 1.05. 
Color, in alcohol, a light flesh tint, much deeper on the large hand. A 
darker spot on the upper surface of the carapax, also on the anterior edge of 
the two first abdominal segments. 
This species lives in pools on rocky reefs at low-tide level, and is capable 
of producing, by clapping together the fingers of the larger hand, a snapping 
noise like that which can be made with the finger-nail. 
Collected at Santa Barbara Island by 5. A. L. Brannan, 
Idotea pulchra. 
Body stifily articulated. Cephalic shield emarginate in centre of front form- 
ing two lobes. 
First thoracic segment concave in front, advancing around the head; first 
four thoracic segments sub-equal in length; 3d and 4th about equal in width; 
three hinder thoracic segments much shorter. Abdomen one-jointed, one 
short partial suture on each margin near thorax, tapering to posterior ex- 
tremity, which is narrow, but concave. Margins of all the thoracic segments 
defiected outwards horizontally. 
Flagellum of outer antenne not quite as long as base, 16-jointed, base some- 
what setose. Inner antennz very short. 
Leneth 1.15 in., breadth 0.52 in. 
When recent, the coloration of this species is very beautiful, consisting of 
red cloudings on a lighter ground. 
The two specimens, male and female, in this collection were brought from 
the W. coast of Alaska, N. of Bhering’s Strait, by W. J. Fisher, Naturalist 
of the U.S. S. Tuscarora, Deep-Sea Sounding Expedition. 
Idolega. Noy. gen. 
Last pair of abdominal appendages operculiform, and concealing all the 
preceding pairs, as in Jdolwa, but with four posterior pairs of legs, with 
