!•;•-' TAfii; SKoCSllKlir. 



are pairoil and aro situated p()st<'ri(Ml\' in the Kodx. In voung spocinicns they arc bag-sliapod. 

 in mature specimens sliaped like a buiuli ol <;rapes; see (). W. Ml'llJJOli, ]894, [)1. XL, fig. 27. 

 Tliey gradually pass into the thin-walled oviducts (whicii are widened distally onlv in 

 I'xceptional cases); these emerge paired, in ino.st case.s on small genital lobes situated 

 in the corresponding places as the copulatory organs of the male. Two recep taenia 

 s e m i n i s are developed, one on each side; each receptacuhim consists of a chitinous capsule. 

 which is sometimes sunk deeply in the body, but in most cases, however, projects freely (in the 

 L'enital lobe) and emerges close to the oxidnct. No parts of the genital organs penetrate 

 lietween the lamellae of the shell. 



Heart always developed. 



Organs of sense: — Lateral eyes most frequently well-developed, 

 less often more or less reduced, seldom ([uite absent; the number of ommatidia varying 

 greatly. — The n a u p 1 i u s or m e d i a n e y e situated rather deep down on the 

 forehead, always developed, .sometimes ((ji^iantocjifris) extremely large. Ventrally close 

 to the nauplius eye there is a r o d - s h a p e d frontal o r g a n, often rather long, 

 sometimes very small (or even not developed at all?). — Some of the limbs have 

 sensorial bristles. 



B r a n c h i a e sometimes developed dorsally on the back of the body. 



The eggs are carried continuously after laying between the shell and the back of the 

 body until they hatch. 



Salt-water forms of moderate size or sometimes even very large (maximum length so 

 far found: 21 mm., Gigantocypris). Most frequently more or less completely confined to the 

 bottom; sometimes, however, they belong entirely to the plankton. 



Special terminology: — Second antenna: — The spine at the base of the 

 natatory bristles of the exopodite is called ,, basal spine". 



Mandible: — It does not seem to be quite right to follow most writers in calling 

 the endite of the coxale a ,, masticatory process" since, at any rate as far as we know, it is not 

 used directly in dissecting food. In the present work it is called (except in the family 

 Asteropidae) simply endite. 



Seventh limb: — The bell-shaped segments distally on the cleaning bristles are 

 called ,, bells"; the most distal of these segments often ,,the end-tongue". The comb-like 

 foi'mations distaUy on this limb are called „end-combs". 



Historical * : — Some of the first publications about forms belonging to this group consist 

 merely of descriptions of species written in very general terms, based exclusively on the outer 

 characteristics of the shell. But even the earliest writers on this subject made an attempt at 



* On account oi profound ilifferen( es between the A s I e r o p i d s and the oilier forms belonging to the 

 group disc ssed here both in their morphology and oecology, the knowledge of the first-named group has developed in 

 a rather independent manner. Because of this it seemed most convenient to me in the present treatise to discuss the 

 history of the investigation of the Asteropiils in n special chapter togelhei- with other p?'ohlems lorHcrninsr 

 this gionp. 



