34 



TAGE SKOGSBERC. 



Hal"cypridae. 



Cypridae, Danvin- 



ulidae, Xesideidae 



and Cylheridae. 



logons to tlio ondopodite. The exopodite is {)o.ssibly quite absent. It does not seem to be 

 impossible, however, that the bristle or bristles found (listn-latcrally on the basale are to be 

 explained as a remains of this branoli. The large lamellit'orm ajipendage, furnished with fine 

 hairs, that is found dorso-proximally on this limb in all the forms of this family known so 

 far. is probably, on the other liand not homologous to the exopodite. It is presumably 

 homologous to an epipodial appendage; this idea is supported both by the position of this 

 appendage — distallv on the part that has been explained as the coxale, i. e. at the same 

 place as the epipodial appendage on the maxilla in a number of forms of the sub-family 

 Cijpridininae — and by its appearance, which bears a rather close resemblance to the epipodial 

 appendage in the last- mentioned group. 



The Halocyprids have a maxilla that resembles very closely, on the whole, the type, 

 that is found in the family Cypridinidae; consequently in the present work quite the same 

 homologization has been carried out in both these groups. The exopodite has, however, 

 quite disappeared. C. Claus points out in his work of 1891 a, p. 26 the occurrence on the 

 inside of the endopodite of ,,ein nach innen gerichteter borstentragender Fortsatz, dessen 

 Deutung Schwierigkeiten bietet"; this process was homologized with the exopodite. This 

 author is certainly mistaken as to this. A similar process with a single bristle is also found 

 in Cypridinids; see, for instance, fig. 13 of Philomedes (Scleroconcha) Afpellofi below.* 

 The epipodial appendage is always absent.** 



The explanation of this limb in the Cypridae, Darwinulidae, Nesideidae and Cytheridae 

 seems, on the other hand, rather uncertain. The proximal part with its three endites 

 of course probably corresponds, as in the preceding groups, to the procoxale and 

 the coxale. But does the palp, as in Cypridinids, Halocyprids and Poly- 

 cop i d s, correspond to the basale of the protopodite and the endopodite or does it represent 

 the basale and the exopodite or only the endopodite or the exopodite? Is the vibratory plate 

 to be considered as homologous to the exopodite or to an epipodial appendage? Neither the 

 relative position of these organs, their morphology or their embryology give any certain infor- 

 mation on these points. The fact that it is presumably the endopodite that has predominated 

 in the development of the maxilla in Cypridinids, Halocyprids and P o 1 y- 

 c o p i d s clearly does not justify us in assuming without further hesitation that the same branch 

 has also predominated in the four families mentioned above; of this the second antenna affords 

 proof. The fact that in the Cyprids, Darwinulids, Nesideids and Cytherids 

 it is, in the case of the mandible, probably an epipodial appendage that is developed as a 



• The same process had been already observed previously both by C. Claus, 18;'i b, and by G. O. Sars, 1887 

 and G. W. Muller, 1890 a. It is true that G. O. Sars did not directly state that this appendage was homologous 

 with the exopodite, but nevertheless he points out (p. 75) that it ,,if0lge sin Beliggenhed aabenbart svarer til det nedadretlede 

 membranase Vedhaeng hos Cypridiniderne og den staerkt udviklede Vifteplade hos Podocoperne" (Translation : 

 On account of its position it obviously corresponds to the downward pointing membranous appendage in the Cypri- 

 dinids and the strongly developed vibratory plate in the Podocopa"). 



•* G. S. Brady, in his work of 1880, pi. XL, fig. 10 reproduces a maxilla of ,,Halocypris atlantica Li'bbock" 

 (presumably Conchoecia serrulata Claus) with a strongly developed vibratory plate, and he includes this character both 

 in the family and the genus diagnosis. As G. O. Sars pointed out (1887, p. 75) it is presumably the vibratory plate 

 on the fifth limb, which, owing to a mistake during the dissection, happened to be attached to the maxilla. 



