4 ME. 0. A. SATCE ON A EEMAEKABLE 



The body is very slender, fully eight times as long as broad, and of almost uniform 

 breadth throughout. Anteriorly it is slightly dorso-ventrally compressed and of 

 subeylindrical form, but tbe depth gradually increases posteriorly, so that the last few 

 segments are cylindrical. The integument is smooth, thin, and membranous, and 

 contains no lime salts. There is no development of pleura, and the epimera are incon- 

 spicuous. It is divided into fourteen distinct segments, comprised of cephalon, seven 

 thoracic and six abdominal ones, all but the cephalon being subequal. They are freely 

 articulated one to another and all with similar powers of flexion. 



The cephalon (PI. 1. figs. 1, 2, 3) is about equal in length to the following two segments 

 combined, and is freely articulated to the following segment. Looked at from above 

 the shape is subquadrate, with frontal margin above the attachment of the antennules, 

 forming a wide evenly triangular projection, the obtusely-angled apex curving slightly 

 downwards between the closely approximated antennules. On each side of the base of 

 this triangular area the margin is incised, so that a narrow lateral lobe is formed 

 between it and the inferior margin. 



I have critically examined the position corresponding to that where Caiman has 

 observed what he thought might possibly be ocelli in Anaspides, but cannot find the 

 slightest indication of any in the present species. 



Viewed from the side the dorsal line is almost straight, curving slightly downwards 

 anteriorly and posteriorly, and slightly depressed in the middle. The lobe on each side 

 is about the width of the basal joint of the antenna, the attachment of which it overlies ; 

 its upper corner is right-angled and the frontal margin meets the inferior margin in an 

 even curve, thence it runs almost straight hindwards for half the length of the head ; 

 from here a definite sulcus runs obliquely backwards for a short distance, then turns 

 straight upwards and merges in the dorsum, where no trace of it can be seen ; this 

 sulcus commences immediately posterior to the insertion of the mandibles, and 

 corresponds to the apparently definite division which separates the head from the thorax 

 in Anaspides. Immediately posterior to this sulcus the inferior margin commences to 

 descend gradually to a depth equal to that of the following segment, then to curve upwards 

 to meet the posterior margin. There is no branchial cavity formed. I can find no 

 trace of any lateral sulcus nor indication of division running obliquely across in the 

 position corresponding to that on the first thoracic somite of Anaspides. 



The eyes are situated on the dorsum, at the angles formed by the union of the frontal 

 margin and the lateral incisions, and quite close to the frontal edge. They are very 

 small, circular, and uniformly black. 



Perceon or Mesosome. — The seven segments are each of equal width to one another, 

 but gradually increase a little in depth posteriorly, the back is evenly arched from side 

 to side, the inferior margins slightly excavated above the attachment of the appendages, 

 and there are no definite epimera. 



In the female just in front of the last pair of legs there is a development of the 

 sternum to form a small pouch (spermatheca), which is described later when dealing 

 with the appendages. 



The Pleon or Metasome is of similar length to the perueon, and its segments subequal, 



