134 TAGE SKOGSBBRG 



as a very short, upward jjointing peg, without bristles. The sixth 1 i m 1) has a more markedly 

 larval type than in the preceding stage; it is represented only by a rounded, unjointed or almost 

 unjointed, weakly two-lobed little plate, of about the same type as is shown in fig. 22, pi. 34, 

 G. W. MtJLLER, 1894; the proximal joint usually has only one bristle; the distal one has no 

 bristles, only numerous stiff hairs. Each f ureal lamella has six or seven claws, of 

 which the two distal ones dominate rather decidedly over the others; cf. fig. 13 of this 

 species in the special part of this work. The lateral eyes, the median eye and the 

 r o d - s h a p e d organ are rather well developed, the median eye, however, is only 

 rather slightly pigmented. 



Stage V: — Shell: Average length, 1 mm. ; length : height = 1,4 : 1. ^^^lile the 

 preceding larval stages were characterized by a shell whose length was somewhat greater in 

 proportion to its height than in the mature female, this stage, like the following, shows a shell 

 in which the proportion between length and height is about the same as in the mature female. 

 The seventh 1 i m b is quite absent. The sixth limb is developed only as a small 

 undifferentiated, downward pointing peg with stiff hairs. The other limbs have about 

 the definitive fundamental type, but have a somewhat more larval appearance than in the 

 preceding stage — especially in the case of the bristles. Each furcal lamella has only 

 five or six claws, the two distal of which dominate over the others even more strongly than in 

 the preceding stage. The lateral eyes are large and fairly well developed, the median 

 eye and the rod-shaped organ are developed but have a decidedly larval appearance; 

 the median eye has scarcely any pigment. 



Stage VI: — This is the youngest free-living larval stage that I found. Shell: 

 Average length, 0,9 mm.; length : height = about 1,4 : 1. Even in this stage the shell has about 

 the same type, when looked at from the side, as in the mature stage. It agrees fairly closely 

 with the preceding stage; the sixth limb is almost as much developed here as in this stage. 



The next stage that I found had not yet left the brood chamber. Its length was only 

 0,6 — (»,7 mm. The lateral eyes were large and well pigmented but had no ommatids 

 developed. The limbs were scarcely developed. Possibly it ought really to be termed an embryo. 



Although the length classes that were observed were thus in a number of cases rather 

 closely related to each other morphologically, there can be no doubt that each of them 

 represents a moult. 



G. W. MCller in his Ostracod monograph, 1894, gives a short description of the three 

 youngest larval stages of Cypridina mediterranea 0. CoSTA. According to this author the larva 

 of this species leaves the brood chamber as soon as it has been hatched from the egg. The 

 youngest free-living larval stage has about the same shape of shell as the mature specimens, only 

 ,,etwas klirzer und hoher". The five anterior limbs have about the definitive type, but the 

 fifth limb ,,mit wesentlich geringerer Anzahl von Borsten uird zahnartigen Gebilden". The 

 sixth limb is already formed, but is very simple; it has a ,,bereits an die definitive Gestalt 

 erinnernde Form",* and has no bristles at all. The furca has five claws, the two distal of which 

 dominate strongly over the others. 



* PI. 34, lig. 21 slinws a lypi- very like Uiat ilcsirilifil by iiii' abovr for Stagv \. 



