202 U.S. NATIONAL MUSEUM BULLETIN 236 



Shape of body as in female; consequently, it has not been figured, 

 but it has been dissected to check identification. The principal 

 points of interest are listed below: 



1. Abdominal somites 1 and 2 separate. The hairhke spinules on 

 somites 1 to 3 are arranged distinctly in transverse rows; no hairs or 

 spinules occur on somite 4. The rows of spinules on somites 2 to 4 

 are interrupted ventrally (fig. 73c). 



2. Antennules apparently 10-segmented. Segment 4 large, in- 

 distinctly separated from segment 5, with a conical process and 

 aesthetasc. Jointing developed between 6th and 7th segments. Seta- 

 tion represented in figure 75e. 



3. Internal spine on basis of leg 1 short and strong, basally with 2 

 short additional spines (fig. 75a). 



4. Endopodite of leg 2 modified; the accurate shape can best be 

 taken from figure 756. In the structure of this leg the male approaches 

 that of A. minutus very closely. 



5. Leg 5 (fig. 73d) with small, distinctly cordate exopodite, strongly 

 narrowed proximaUy and attached to baso-endopodite by means of 

 a narrow strip. There are 5 marginal setae: 2 at external, 2 at in- 

 ternal border, and 1 at apex. Proximal part of external margin 

 spinulose. Baso-endopodite with 2 apical setiform spmes of equal 

 length. External margin spinulose; at distal end of this row of 

 spinules there is a short tooth. 



6. Armature of genital plates (leg 6) composed of 3 setae. 

 Remarks. — Amphiascus hirtus is very closely allied to A. minutus 



and a careful comparison of both descriptions shows that the only 

 definite points of difference are: 



1. Spinosity of the abdomen in A. hirtus. 



2. Small differences in the shape of leg 5, especially the exopodite. 



3. Greater length of antennules and antennular segments in A. 

 hirtus. 



On the basis of the two characters mentioned under 2 and 3, A. 

 minutus shows a considerable variability. 



A. hirtus has been recorded so far from Port Said, Qantara, and 

 Port Taufiq in the Suez Canal zone (Gurney, 1927: 9 0.51 mm., cf 

 0.45 mm.) and from Campbell Island in the South Pacific (Lang, 

 1934). The present specimens originate from a sand sample taken 

 some 80 feet from the reef margin at Falarik in the Ifaluk Atoll. 



