132 TAGE SKOGSBERG 



Summary f.f (hn: Tliese instances ought to show better than many words the necessity of proceeding with 



rniicsiii. ^j^^ greatest caution in applying the ,,law". 



The weak j)iiint in the proofs obtained by this author from the genus Conchoecia is that 

 they are based on a material that was caught at a region so rich in similar and closely-related 

 species as the Bay of Biscay. In earlier stages it is almost or quite imj^ossible to distinguish 

 closely related species of this genus with certainty by means of morphological characters. 

 Investigations of this Icind ought, of course, to be based either on material in aquariums or, 

 preferably, on material from localities at which there are no forms that are closely related to 

 the species investigated, and the material should be submitted to a very careful morphological 

 investigation. 



On the other hand it must be definitely pointed out that some of the examples 

 given by G. H. Fowler strongly support Brooks's law as it is formulated by this writer. 

 Among these forms there is especially Conchoecia imbricata; this form is very characteristic 

 and even during the earliest larval stages it seems to be distinguishable with certainty from 

 other forms found in the region investigated. The result of this author's measurements of 

 Cypridina ( Macrocypridina) castanea, which is mentioned above, also seems particularly 

 noteworthy, but the material of this species was unfortunately too sparse for the result 

 obtained to have any decisive importance. 

 .Vy own im-fsii- I uow pass on to givc an account of some observations made by myself, which may to 



gniionof iiii.< imv gQ^e pxtcut help to increase our knowledge of this ,,law". For the terms given to the 



as applied on tin' T_a-ii i i-i -i 



Ostracods. dilierent larval stages see p. 60 above, the chapter on general termmology; lor the method 



of measuring the length of the shell see p. 13 above of the introduction. 



Sub-order: Cypridiniformes. 

 Cijpridiiiiforn,i"<. Cypridifia (Doloria) pectinaia. 



All the individuals whose measurements are given below were caught at the 

 same time and at the same place: S. A. E. station 60, the eastern exit of the Beagle 

 Channel, Tierra del Fuego, 100 m. deep. It seems certain that all these specimens belonged 

 to this species, partly because of morphological reasons, partly because this species seems 

 to be the only or at any rate quite the dominant representative of the sub-family Cypridimnae 

 in this region. 



Six free-living larval stages could be distinguished: 



(i e n e r a 1 description of the larval s t a g e s : ^ — ■ 



Stage I : — 



Male: This is very like the mature stage. Shell: Average length, 2 mm.; length: 

 height = about 1,5: 1. The first antenna is of about the same typo as that of the 

 matvire female; it is quite without secondary sexual characters. S e c o 7i d antenna: 

 The endopodite is of about the same type as that of the mature male but has a rather decided 

 larval appearance; its end joint is somewhat straighter and it is obvious that it cannot be folded 

 back on its predecessor; cf. fig. 12 of this species. The posterior limbs differ from 

 those in the mature stage only by having a more larval appearance and having the bristles 



