I'.U TAOE SKO()Slii;i{(i 



Tvpo 1: All the furcal cluws an' wrll di'fincd I'roin the lamellae and dorro.iRo unifonnlv in 

 leniithandstren^th the more proxinially they aiesituated. This type is found in (\((\) acuminatd 

 {U. \V. Mri.l.KiO and C. (C.) natatis ((i. S. HuAhN ). Ct. (1. W. M('LI-KH. IIIOO U, pi. 11. fifi. :i. 



Tvpe 11: The second fureal claw is united wiiii the lamella, the others are all well defined 

 proximallv: all the flaws decrease undiuniK in leuLitli and sticn^tli the more proximally they aic 

 situated, sometimes, perhaps, the third of them is somewhat weaker than one would expect from 

 its positi(m. — This type is fo\ind in ('.(( '.) dctitafa ((t. \V. Mi'l.l.Kli), ( '. (( '.) inermis (G. \\. MOLLKl;) 

 and ('. (C.) sinuosa ((}. W. Mi l.l.KK). W- (i. W. MdLLKi!, 1906 I). ]>\. 11., figs. 21, 10 and 11. 



Type III: The second furcal claw is united to the lamella, all the others are well defined 

 proximally; all the claws decrease fairlv uniforndy in length and strength the more proximally 

 thev are situated, with the exception of the third, which is considerably shorter and weaker 

 than one would expect from its jjosition. — This tyjie is found in f\ (f.) amfhiacanilia (0. \\. 

 Mri.I.ER). Cf. this author. 1906 h. pi. III., fig. 11. 



Tv])e IV: The second and fourth furcal claws are united to the lamella, all the others 

 are well defineil proximally; all the claws decrease uniformly in length and strength the more 

 proximally they are situated, with the exception of claw no. 3, which is considerably shorter 

 and weaker than one would expect from its position. — This type is found in the femah's of 

 C. (C.) serrata (G. \V. Mfl.LER) [~- C. (C.) lepi/Iophora {(i. ^^^ Mi'iJj;H), cf. below, note on 

 ('. (C.) serrata, var. affirwam]. Cf. (!. W. MClleh, 1906 b, pi. III., fig. 19. 



These types are found in the sub-genera Vargula and Siphonostra as follows: 



Tvpe I: Appears to occur in most of the species of the sub-genus Vargula, as for instance 

 in C. (V.) megalops; see the fig. 16 of this organ of this species in this work. 



Type II: Found in Cypridina Hilgendorfi U. W. MiJLLER, a species that is certainly 

 to be referred to the sub-genus Vargula. See (4. W. MUller, 1890, pi. XXVI., fig. 1. 



Tvpe III: Found in Cypridina Vanhoffeni G. W. MOller, a species that certainh- 

 belongs to the sub-genus Vargula. Cf. G. \\. Mlller, 1908, pi. V., fig. 4. 



Type IV: Found in the female of Cypridina (Vargula) norvegica (W. Bau^d); the third 

 furcal claw is, however, only rather slightly weakened; cf. the description of this species given 

 below. In addition we find this furcal type in the only representative of the sub-genus Siphnn- 

 ostra. The resemblance between G. W. MCller's drawing of the furca for Cypridina (C.) 

 serrata. 2 and the figure given below in this work of the furca in Cypridina (Siphnnosfra) spinifera 

 is really almost perfect. 



The occurrence of the second, third and fourth furcal types in these three sub- 

 genera can certainly not be explained otherwise than by convergence. One can as a matter 

 of fact scarcely avoid the idea that in these groups there is to be found a ,, tendency" in the 

 second and fourth furcal claws to unite with the lamella and in the third furcal claw to be 

 reduced in length and strength! 



Other examples of convergence within this sub-family could be given, but the one given 

 above, which is the most striking, .should, at least in this connection, be sufficient. 

 Important Among all the characters I have had occasion to observe those which seemed to 



me the most noteworthy for the solution of this problem were the equipment on the b- 



characters. 



