298 GEOLOGICAL SURVEY OF THE TERRITORIES. 
male keeping the eggs in place. 1st (Limnetis), or usually the Ist and 
2d, pair of feet in the male provided with « hand; the 4th, 5th, and 6th 
endites modified to form a claw, finger, and thumb-like clasping organs. 
Posterior segments each bearing a pair of spines; the telson large, com- 
pressed, often spined, and bearing a pair of caudal appendages. Larve 
nauplius-shaped. 
Subfamily LIMNETIN A‘ Packard. 
Shell nearly spherical, with no lines of growth; rostrum very large and 
broad at the end, mucronate in the females, broad and truncate in the 
males; 10-12 pairs of feet ; in the males only the Ist pair provided with 
a hand; terminal segments of the body not spined; telson undeveloped. 
But a single genus, Limnetis. 
Genus LIMNETIS Lovén. 
Limnetis Lovén, Kongl. Vet. Akad. Handlingar, Tab. IV, 203, 1845; 
Ofversigt Vet. Akad. Férhandl. 57, 1846; Wiegmann’s Archiv, i, 208, 
1847. 
Hedessa Lievin, Neueste Schrift. der naturf. Gesellsch. in Danzig, IV, 
Heft II, 4. Tab., I, II. 
Hedessa Siebold, Neueste Preuss. Provincialbl. VII (XLI), Heft 3, 198, 
1849. 
Carapace bivalved, nearly spherical, oval, smooth; polished fine punc- 
ture-like marks in the parenchyma of the shell, giving it the appearance 
of being finely punctured ; no beaks or umbones. Head large, the front 
bearing the eyes enormous, and produced into a very large rostrum, 
either truncated in ? and either mucronated or truncated in ¢ in front. 
Eyes small, sometimes separate. First antenne minute, slightly el- 
bowed, with indications of three joints; second antenn with scape or 
base rather short; the flagella rather short, composed of from 15 to 21 
joints, with remarkably long sete. From 11 to 12 pairs of feet; in the 
males the anterior pair converted into a complicated hand; the end of 
the abdomen blunt, simple, with no spines. 
The species of this genus are readily recognized by the spherical 
small, smooth shell, with no lines of erowth, entirely inclosing the 
animal; by the enormous head, the large broad rostrum; the few feet, 
there being but one pair of hands in the males, instead of two, as in 
Estheria, and by the ‘simple unarmed telson. The antenne are shorter 
and thicker than in Wstheria. They are sometimes mistaken. by shell 
collectors for specimens of Cyclas or Pisidium. They swim on their 
backs, with the shell a little open, in a graceful but not very rapid man- 
ner compared with the Ostracoda. : 
Synopsis of the species. 
Shell subspherical, small, front of head of male narrow; 
second antenne 16-jointed ; flabellum very large....-- LD. gouldii. 
Shell large, suboval; front of male broad and square ; : 
second ’antenne 14 and 17-jointed; flabellum remark- 
alloys amammoiwis ) 208i 215 ate) Sena Na RL RR Cite ph a sap DL. mucronatus. 
Shell large, suboval; front broader than in any other spe- 
cies except gracilicornis ; autenne 20-jointed; gill very 
large, flabelium short and broad..........-..--....- L. brevifrons. 
Shell small, subspherical; front very broad; antenne long, 
20 jOimbeM ee 5 Heys MAO eRe Bae Ei Seni Uh Ue eae LL. gracilicornis. 
