TETRADECAPODS. 285 
form, the change being induced by the greater or less saltness 
of the water. Artemia produces young by budding (parthe- 
nogenesis) as well as from eggs. e a@ ob 
A species observed near Odessa 
produced. females alone in warm 
weather; and only in water of [ 
medium strength were males f—o 
produced. The eggs of <Arte- ee 
mia fertilis have been sent in ‘“ 
moist mud from Utah to Mu- 
nich, Germany, and specimens 
raised from the eggs by Siebold, 
proving the great vitality of the 
eggs of these Phyllopods, a fact 
paralleled by the similar vitality 
of the eggs of the king-crab. 
Fig. 244 6 represents the Nau- ,_, 
plius of the European brine- 
shrimp. 
Order 4,— Edriophthalma.— 
To this order belong the sow- 
bugs (Zsopoda) and the beach- 
fleas (Amphipoda). In these ,,ig,, 247.—Brine- shrimp, Aniemi, 
3 gracilis, enlarged. a, first antenna ; , 
Crustacea there is no cephalo- second antenna or clasper; ¢, stalked. 
thorax, but the head is small, oon eee 
bearing two pairs of antenne, and a pair of jaws, and three 
pairs of maxilla. The thorax is continuous with the abdo- 
men. Respiration is performed by lamellate or leaf-like. 
gills on the middle feet in the Amphipods, or on the hinder 
= abdominal feet in. 
the Isopods. The 
lowest Isopods are 
parasitic, they 
Fig. 248.—Artemia fertilis from Great Salt Lake. ¢, ‘ 
egg-sac ; ¢, male claspers. > graduate into the 
ane nna eee, 
-. 
oe lem N 
Eas 
Amphipods, and. 
the higher Amphipods are connected with the shrimps (De- 
capoda) through a group (probably a suborder) of synthetie 
forms (Palewocaris, Acanthotelson and Gampsonyz, Fig. 
249) such as are found in the coal formation of Illinois 
