OG TAdK SKOOSIllOliO 



these, C. Claus antl (i. Alm. For this i-eason it seemed to me that the most obvious course in 

 discussing this problem was to put my answer into the form of a criticism of Ct. W. Ml'LLER's 

 exposition of the results gained by him. 

 c. u. Miii/frsop,- Gr_ \V_ MtlLLER depicts the life, organization and development of the Protostracods 



iiKiii (if ihe Prnt- ,, , ■, p I, 



, , on the whole as loiiows: 



nslracoth. 



Lif,'. The Protostracods were freely swimming organisms, but did not travel far 



from the bottom, often attaching themselves to hydrophytes ,,ohne indessen umherzukriechen"*. 

 They already had a calcified s hell which enclosed the whole body and which was shut 

 by a closing muscle which went through the body. The shell was ,,vermuthlich" characterized 

 by a rostral incisur ,,fiir den Austritt des AuBenastes der 2. Antenne'' and bv an arched ventral 



S/lrll. 



Seginfiitalion nj ilu 

 hodi/. 



.Xiiiiihnr oj IiiiiIj.^ 



/''ir>;l Ohh'tnia. 



The body was s e g m e n ted e x t e r n a 1 1 y; there were at least eleven segments 

 behind the head, of which only some had limbs. 

 iirari. Aiiiiieiiiar,/ ^ heart was dcvelopcd. The alimentary organs were of the same simple 



tvpe as in the recent C y p r i d i n i d s. There were well-developed c o m p o u n d late r a 1 

 e yes and an u n p aire d m e d i a n e y e divided into three parts. 



There were eight jsairs of limbs, and a ninth liad perhaps already become employed as 

 a copulatory organ. Only four of the limbs belonged to the head; the appendage corresponding 

 to the second maxilla of other Crustacea was absent. 



The first antenna had eight joints. It was probably most similar to that of the recent 

 C y p r i d i n i d s, wliich is a sensory and a locomotory organ at the same time. ,,Von einer 

 solchen Form konnte sich ebensowohl die vorwiegend der Bewegung dienende Form der Podo- 

 copa, wie die ausschliefilich oder fast ausschlieBlich als Sinnesorgan fungirende mancher Myodo- 

 copa entwickeln. Unzweifelhaft hat ein Wechsel, der zum Ueberwiegen der einen oder anderen 

 Function gefiihrt hat, wiederholt stattgefunden." 



Second antenna: — This had a two-jointed protopodite and a well-deve- 

 k)ped endo- and exopodite. The endopodite was four-jointed, the exopodite composed of a 

 rather large number of joints. Of the recent s t r a cods the P o 1 y c o p i d s would 

 have the most primitive second antenna; these forms would differ from the original type chiefly 

 in the structure of the protopodite. The protopodite of this limb would have had a very different 

 fate in the Cypridinids, Halocyprids and P o 1 y c o p i d s on the one hand 

 and in the other s t r a c o d s on the other. In the former groups the two protopodite joints 

 liave pointed in the same direction and then gradually have been quite united to each other. 

 In the latter the protopodite was distinguished by the fact that the two joints together formed 

 an upward pointing knee; in most of them it became single-jointed afterwards by the total 

 disappearance of the distal joint; this joint is still found only in the genus Cytherella. In the 

 ( ' y }) r i d i n i d s and the H a 1 o c y }> i- i d s the endopodite is more or less completelv 

 reduced. „Da6 bei einer fast ausschlieBlichen Verwerthimg der 2. Antenne als SchwimmfuB 



Srroiid inilfhitd. 



* r;. W. .\IiJLi,i:n Wfitc's, |i. I'.lS, llial llii-y wiTc ..in drr Li^iriiswcisc drn H a 1 o r y p !■ i d c ii am narh.slpii". 

 Wlicii lie wi'oir this, hi' was of thi' tipiiiioii Ihal Ihf H a I (i c y |i r i d s livo chipfly al llii' luilluni and ..nuf 

 zi-itwi'ilig si-liwiniiiHMid anl'slciycn". ISll'i. p. I!!: iiT roursi' he gavi' up lliis (i)iini(in later on. 



