36 CRUSTACEA BRANCHIOPODA chap. 



appendage, 2-jointed, the second joint lamellar. A. salina, 

 Linn. — Brine pools of the Palaearotic region. 

 c. Hinder abdominal segments united with telson to form a fin ; anal 

 lobes absent. 



Thamnocephalus, Packard — Head with a branched median pro- 

 cess of unknown nature. Only species T. platyurus, Packard 

 — Kan.5as, U.S.A. 

 B. Nineteen pairs of praegenital ambulatory limbs. 



Polyartemia, Fischer — Second antennae of c? forcipate ; ovisac 

 of 5 very short. Only species P. forcipata, Fisch. 

 Fam. 2. Apodidae.^ — Carapace well develojoed as a depressed shield, 

 covering at least half the body. Eyes sessile, covered ; no male clasping 

 organs ; anal lobes long, jointed cirri. 



Apits, Scopoli — Telson not produced backwards over the anus ; 



endites of first thoracic limb very long. A. cancriformis, 



Schaeffer — Britain, Europe, Algiers, Tunis. A. austrcdiensis, 



Central Avistralia. 



Lepidurus, Leach — Telson produced backwards to form a plate 



above the anus ; endites of first thoracic limb short. L. pro- 



ductus, Bosc. — Central Europe. L. viridis. Southern 



Australia, New Zealand, L. patagonicus, Bergh, Argentines. 



Fam. 3. Limnadiidae. — Body compressed ; carapace in the form of a 



bivalve shell, the two halves capable of adduction by means of a strong 



transverse muscle ; second antennae biramous, alike in both sexes ; in the 



male, the first or the first and second thoracic limbs prehensile ; telson 



laterally compressed. 



A. Only the first thoracic limbs prehensile in the male ; the carapace 



spheroidal, without lines of growth ; head not included within 

 the carapace-chamber. 

 Limnetis, Loven — Compound eyes fused ; anal spines absent ; 



ambulatory limbs 10-12. L. brachyura, 0. F. Miill (Fig. 3, 



p. 21). — Norway, Central Europe. 



B. The first and second thoracic limbs prehensile in the male ; carapace 



distinctly bivalve, enclosing the head, with concentric lines of 

 growth round a more or less prominent umbo. 



Eidimnadia, Packard — Carapace narrowly ovate, with few (4-5) 



lines of growth. E. mauritani, Gu6rin — Mauritius. E. 



texana, Packard — Texas, Kansas. 

 Limnadia, Brongniart — Carapace broadly ovate, with numerous 



lines of growth, without distinct umbones ; L. lenticularis, 



Linn. — Northern and Central Europe. 

 Estheria, Etippell — Carapace with well-marked umbones and 



numerous lines of growth, oval ; E. tetraceros, Kryneki — 



Central Europe. 

 Leptestheria," G. 0. Sars — Carapace compressed, oblong. Ros- 



1 Bernard, loc. cit. p. 19 ; Baird, Proo. Zool. Soc. 18.52, p. 1 ; Sayce, Proc. Hoy. 

 Soc. Victoria, xv., 1903, p. 224. 



2 Sars, Arch./. Math, og Naturvidensk. xx., 1898, Nos. 4 and 6. 



