studies on marine Ostracods 



769 



inner edge of the coxale there are three groups of stiff hairs, Distally on this joint there is, in 

 addition, an oblique transverse row of fine hairs. On the inner edge of the basale there are stiff 

 liairs, situated close together. Apart from these tliere are rather numerous hairs scattered 

 on this joint. The exopodite is bare, the endopodite is hairy. 



F u r c a (see the appended fig. 8) : — This is almost exactly of the same type as in the 

 species just mentioned; see G. W. MtlLLER, 1894, pi. 7. fig. 24. It has consequently seven 

 moderately long and strong claws, which decrease uniformly in size the more posteriorly they 

 are situated and are all well marked off from each other. The pectination of the claws is uniform. 

 Between all the claws there is a triangular process, the one between claws no. 1 and 2 being 

 rather large, the others decreasing in size and strength posteriorly; the posterior one is quite 

 small. There is also a little spine behind the posterior claw. The larger ones of these processes 

 are furnished distally with a collection of fine hairs. In front of claw no. 1 there is a triangular 

 pointed process, about as large as or somewhat larger than the process between claws nos. 1 

 and 2. On this spine there is a series of rather strong small spines, which continue some distance 

 up on the lateral side of the lamella. On the inner side the lamella is partly furnished with 

 short hairs. Just behind the claws there is an unpaired process (the end of the body) with a 

 single bare bristle, somewhat shorter than the posterior furcal claw. 



Dorsally of the furca there are on the back some transverse folds furnished with a series 

 of fine, stiff hairs. 



On the front at the same place as the rod-shaped organ in Cypridifii formes and Halo- 

 cypriformes there is a low swelling, furnished with two long-haired subequal bristles about as 

 long as the dorsal side of the second joint of the first antenna; see the appended fig. 9 (a character 

 from which this species is named). 



The upper lip is rather helmet-shaped (fig. 9) and has some groups of fine, stiff hairs. 



Remarks: — On account of the incompleteness and uncertainty of the descriptions of Relation to ot. 



most species belonging to this genus it is exceedingly difficult to decide with certainty the 

 systematic position of the form described above. It is certainly very closely related to the 

 species P. frequens G. W. MOller which has been mentioned on several occasions above. 



The most curious thing about this species of mine seems to be the two bristles on the The 

 front at the place where the rod-shaped organ is found in C y p r i d i n i d s and H a 1 o - 

 c y p r i d s. As there are a couple of bristles at about the corresponding place in both Cope- 

 poda and Cladocera it seems to me not improbable that we are concerned here with a very old 

 character; cf. p. 96 above and C. Claus, 1891 a, p. 18. 



forms. 



bristles on 

 forehead. 



Habitat: — Monaco, just off the harbour; depth 200 m.; fine clay; 27. III. 1916: 1 mature 

 female; K. M. S., on slides (auctor coll.). 



Zoolog. bidrag, Uppsala. Suppl Bd. 1, 



97 



