218 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
Genus EUCHIRELLA Giesbrecht, 1888 
EUCHIRELLA BELLA Giesbrecht 
PLATE 8, Ficure 84; PLate 9, Fiaure 92-94, PLate 19, Ficures 247-248, 261-265 
Buchirella bella GresprecHt, Atti Accad. Lincei, Rome, ser. 4, vol. 4, sem. 2, 
p. 336, 1888; Fauna und Flora des Golfes von Neapel, monogr. 19, pp. 233, 
244, pl. 15, fig. 26, 1892. 
Buchirella amoena GiesBREcHT, Atti Accad. Lincei, Rome, ser. 4, vol. 4, sem. 2, 
p. 336, 1888. 
Euchirella aména GirssRecHT, Fauna und Flora des Golfes von Neapel, monogr. 
19, pp. 233, 244, pl. 15, fig. 20, 1892—Rosg, Rés. camp. sci. Albert de Monaco, 
No. 78, pp. 21-23, pl. 1, fig. 3, 1929. 
Stations 15; 4638; 4665; 4667; 4700; 4710; 4715; 4716; 5102. In 
1888 Giesbrecht established two new species of this genus—bella, 
based upon a single female from the eastern Pacific south of the 
Equator, and amoena, based upon a single male from the eastern 
Pacific north of the Equator. In his Naples monograph he gave a 
very brief (five lines) description of bella and a still briefer (two 
lines) one of amoena, each with a single figure. Since the original 
discovery, amoena has been reported three times. It was merely 
named by Scott in the Stboga plankton and by Esterly from off south- 
ern California, but was given a detailed description by Rose in the 
Monaco plankton with 15 figures. Except for Sewell’s record from 
the Indian Ocean (1929, p. 109) the original specimen of bella has 
remained the only one recorded up to the present time. But the dis- 
covery of 5 amoena males and 20 della females in the surface tow at 
station 4700 suggested that they were male and female of the same 
species, as can be seen from the complete description of an Albatross 
female given below for comparison with Rose’s excellent description 
and figures of the male. There is no doubt that they are the male and 
female of the same species. The name bella takes precedence over 
amoena. 
Female.—Metasome elliptical, twice as long as wide; forehead 
slightly pointed ; rostrum short and conical ; posterior corners smoothly 
rounded. Urosome one-fourth as long and wide as the metasome; 
genital segment asymmetrical, protruding to the left and making the 
segment wider than long. The three abdominal segments are about 
the same length and width and combined are as long as the genital 
segment but narrower. Caudal rami as wide as long, widely separated 
at the corners of the anal segment and divergent. 
The first antennae are slender and reach the tips of the caudal 
rami; they have long filiform setae on several of the segments but 
lack the aesthetasks so numerous in the male. The exopod of the sec- 
ond antenna is not quite three times as long as the endopod ; the termi- 
nal segment of the latter has six and five setae as stated by Giesbrecht. 
