studies on marine Ostracods 



479 



of the process to the main spine is somewhat greater than the distance from the latter to the 

 proximal ventral spine. The dorsal bristle is attached somewhat nearer to the point of the 

 process than its distance from the main spine and about as far as its own length distally of the 

 latter; it extends to a distance of almost half its length distally of the point of the process. The 

 dorsal serrate teeth are rather large. The main spine is unusually powerfully developed. There 

 are five or six ventral spines, in most cases rather strong, of which the two distal ones point 

 proximally ; the distal one of these spines is sometimes even of the same size and type as the main 

 spine. On the part distally of the main spine there are only a few transverse rows of hairs, one 

 or two were observed. The rod-shaped process has four short and powerful distal spines. 

 Basale: The backward pointing process is of about the same type as in the preceding species 

 (fig. 9), but four or five triaena bristles were observed and the glandidar papilla was somewhat 

 more powerfully developed. The dorsal side of this joint has about ten to twelve rather short 

 bristles with short hairs (cleaning organs? they are often very dirty); these bristles are spread 

 along almost the whole of the joint and between them there are numerous short, strong, pointed 

 spines, arranged in groups; in addition there are dorsally on this joint groups of short, stiff hairs. 

 The exopodite (fig. 7) is, even if its two distal bristles are included, somewhat less than 

 half the length of the dorsal side of the first endopodite joint. E n d o p o d i t e (figs. 7 and 11): 

 The shortest of the three ventral bristles on the first joint is only armed with short, fine 

 hairs; of the two others one has from about seven to nine pairs of short secondary bristles 

 proximally of the long ones, the other has either no such short bristles or only a few (one to 

 four were observed). This joint is armed antero-distally with four short, powerful, pointed 

 chitinous spines (from which the species derives its name); cf. fig. 10. Second joint: 

 This has four rather short proximal bristles, subequal or only differing rather slightly in 

 length; the longest of these is only about from a quarter to a sixth of the length of the main 

 bristle a. Between the main bristles b and c there is a long, narrow bristle with short hairs. 

 The medial cleaning bristles on this joint are very numerous, but vary. Four specimens that 

 were investigated showed the following conditions: 



Type specimen: Right mandibk 



7 bristles in a distinct lower row. 



>S -J :: :: :; UppCr ,, 



3 ,, ,, ,, ,, row inside the main bristle b. 

 1 bristle above bristle no. 1 of the latter row. 

 1 ,, between the main bristles a and b. 

 1 .. close to the main bristle a. 



Left 



8 bristles in a distinct lower row. 



7 „ ,, V ,, upper ,, 



1 bristle above bristles nos. 3 and 4 of the latter row. 



1 ,, ,, .. .. 5 ,. 6 ., ,, 



2 bristles inside the main bristle b. 

 I bristle between the main bristles a and b. 

 1 ,, close to the main bristle a. 



