194 TAr.E SKOosHRiir, 



Type 1: All the fuical claws are well defined from tho lamellae and decrease uniforinly in 

 length and strength the more jiroxinially they are situated. — This type is found in C. fC.) acuminata 

 (G. W. MfLLElO and C. (V.) natans (G. 8. Bhai»\). Cf. G. W. MOller. 1906 b, pi. II. fig. 3. 

 Type II: The second furcal claw is unitetl with the lamella, the others are all well defined 

 proxiraallv: all the claws decrease uniformly in length and strength the more proximaUy they are 

 situated, sometimes, perhaps, the third of them is somewhat w^eaker than one would expect from 

 its position. — This type is found in C. (C.) dcntatu (G. \V. Mii.LKR), C (C.) inermis (G. \V. MULLER) 

 and C. (C.) .nnuosa (G. W. MClleh). Cf. (4. W. AlL'LLKl^, 1906 b, pi. II.. figs. 21. 10 and 11. 

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

 proximally; all the claws decrease fairly uniformly in length and strength the more proximaUy 

 thev are situated, with the exception of the third, which is considerabl\- shorter and weaker 

 than one w^ould expect from its position. — This type is found in (\ (('.) amphiacanfha (G. W. 

 MOller). Cf. this author, 1906 b. pi. III., fig. 11. 



Tvpe IV: The second and fourth furcal claws are united to the lamella, all the others 

 are well defined proximaUy; all the claws decrease uniformly in length and strength the more 

 proximaUy they are situated, with the exception of claw no. 8. which is considerably shortei- 

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

 C. (C.) serrata ((). W. MulleR) [^ C. (C.) lepidophorg, (G. AV. MCller), cf. below, note on 

 ('. fC.) serrata, var. affirmans]. Cf. (J. \V. Ml'LLER, 1906 b, pi. III., fig. 19. 



These types are found in the 8ub-genera Vargula and Siphonofttra as follows: 

 Type 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 G. W. MULLER, a species that is certainly 

 to be referred to the sub-genus Vargida. See G. W. MtlLLER, 1890. pi. XXVI., fig. 1. 



Type III: Found in Cypridina Vanhoffeni G. \V. MUller, a species that certainl\- 

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



Type IV: Found in the female of Cypridina (Vargula) norvegica (W. Bajrd); the thiid 

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

 helow. In addition we find this furcal type in the only representative of the sub-genus Sz'p/K/n- 

 ustra. The resemblance between G. \\ . MCller's drawing of the fuira for Cypridina (C.) 

 serrata, ¥ and the figure given below in this work of the furca in Cypridina (Siphonostra) spinifer(( 

 is really almost perfect. 



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

 genern 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 w'ithin this sub-family could be given, but the one given 

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

 Imporuiiii Among all th(> characters I have had occasion to observe those whicji seemed to 



nu' the most noteworthy for the .solution of this problem were the equipment on the b- 



rlinriiclers 



