CRUSTACEA. 
345 
Eighth stage. Length of the shell 0*54 mm., height 0*34 mm. This 
shage is only perceptible from the slight increase in the length of the feet 
and the furcal appendages and from the permanently characteristic size and 
form. Fig. 8. 
It is therefore of much importance in the description of new 
species, both fossil and recent, that carcinologists should bear in 
mind that changes take place in the form as well as the size of 
the shell, all of which Claus has delineated in two plates. 
Hr. G. O. Sars (Vid.-Selsk. Forhand. for 1865) has commu- 
nicated a memoir on the Norwegian marine Ostracoda (pp. 130). 
After a short introduction on the previous researches of various 
authors, he proposes three great groups, of which Cypris and 
Cy there are types of the first, Cypridina and Conchcecia are 
types of the second, and Polycope and Cytherella are types of 
the third : — 
I. Antennae inferiores simplices, subpediformes, geniculatoe, ad apicem im- 
guiferae, antennis superioribus parum dissimiles. Antennae utriusqiie paris 
sive longe setiferae et natatoriae sive breviter pilosae et ad natandiim ineptae. 
Mandibulae distinctae, ad extremitatem inferiorem plemmqiie fortiter dentatae, 
palpo mediocri appendice instructo branchiali plus minusve evoluta. Maxillae 
primi paris lamina praeditae magna branchiali : PodocopA. 
A. Pedum 2 paria, ultimiim intra valvulas inflexum. Pbstabdomen 
[posterior portion of pleon] ranios duos plerumque sat elongatos et angustos, 
ad apicem unguiferos formans Cyprididcp.. 
B. Pedum 3 paria, omnia ambulatoria et inter se consimilia antieeque 
vergentia. Postabdomen [posterior portion of pleon] rudimentare, lobos duos 
minimos formans. Antennae minime natatoriae Cytheridee. 
II. Antennae inferiores biramosae : — 
A. Ramo altero rudimentari, immobili, altero elongato cylindrico, flexi- 
bili, multiarticulato, setis longis natatoriis uniserialiter obsito, parte basali 
permagna et crassa, musculis impleta. Antennae superiores vix natatoriae. 
Palpus mandibularis permagnus, geniculatus, subpediformis, appendice 
branchiali destitutus. Maxillae primi paris lamina branchiali carentes. Post- 
abdomen [posterior portion of the pleon] in laminas duas latas postice un- 
guiferas divisum : Myodocopa. 
a. Pedum unum solummodo par forma singulari, appendicem elon- 
gatam supra curvatam, flexibilem, annulatam, vermiformem, apicem versus 
spiniferam formans. Antennse stiperiores magnae, distincte articulatae, ad 
basin geniculatse. MandibularUm pars propria obsolescens. Maxillae secundi 
paris lamina magna branchiali instructae. Oculi compositi, pedunculati, 
longe sejuncti ; inter ambos antice oculus simplex magnus ettentaculum breve 
frontale ; Cypridinidee. 
h. Pedum 2 paria, posterius minimum et rudimentare, anterius iit 
maxillae secundi paris lamina branchiali parva et lobata instructum. An- 
tennae superiores feminae parvae et d' biles, immobiles et distincte articulatae. 
Mandibulae distinctae. Oculi nulli. Tentaculum frontale permagnum et 
plerumque ad apicem dilatatum Conchoeciidce. 
B. Ramis ambobus bene evolutis, mobilibus et natatoriis. Antennm 
