CYCLOPOIDEA. 1087 



Cephalo thorax naked, three-jointed, rounded behind. Female: — Ante- 

 rior antennae hardly shorter than the body, the last joint longer than 

 the others ; a few remote setae very long and straight, besides two 

 that are very long and bent. Apical setae long, posterior antepenult 

 about as long as the antepenult joint. Caudal setae straight, the 

 second usually as long as the body. Eggs blue. Male ; — Anterior 

 antennae a little shorter than the body, slightly bent, setae short, 

 the longer scarcely exceeding the length of the apical joint. Caudal 

 setae about as long as the abdomen. 



Plate 77, fig. Va, lateral view of female, enlarged ; b, mandible, more 

 enlarged ; c, maxilla ; d, maxilliped. Fig. 2 a, male, enlarged; a', upper 

 view of front; b, second pair of antennae; c, one of the natatories; d, 

 e, genital feet, d being the left. / 



The females were collected abundantly in the Atlantic, October 15, 

 18, 20, 24, 26, 27, 29, 30, 31, November 1, 3, 5, 9, 12, 1838, latitude 

 9° north to 0°, longitude 17°-23° west; and latitude 0°-13° south, lon- 

 gitude 17°-32° west; also, May 11, 1842, latitude 7° south, longitude 

 20° west. The males were collected October 18, and November 1, 

 1838. The hour of collection was usually at 4 a.m., before daylight. 



Length, one-eighth of an inch. Some red about the thorax ; eggs 

 bright blue. 



The propriety of uniting the two Euchaetae, here described as male 

 and female, is still quite uncertain, and rests mainly on the fact that 

 they were found in the same part of the Atlantic, and no other male 

 corresponding to the female, or female corresponding to the male was 

 obtained. Besides this, the anterior legs are similar in the size of the 

 apical multiarticulate part. 



In the female, the first of the four cephalothoracic segments sometimes 

 appears divided by an imperfect articulation, near the centre of the 

 cephalo thorax. The first of the joints of the abdomen is a little the 

 longest. The caudal stylets are shorter than the last joint, and their 

 apices are generally nearer than their bases ; the setae are not as long 

 as the abdomen, except the second ; this is curved, and in one specimen 

 was longer than the body, while in another it was a little shorter. 

 The anterior antennae are in general very even ; the long posterior 

 apical seta is nearly half as long as the antenna, and a shorter one 



