Chemistry and Physics. 1389 
specimens of large size, taken in the breeding season, in spring. 
At other seasons and in smaller specimens, these charac’ ers are 
not so obvious. Acetabulum large, separated from the body by 
a well-marked constriction. 
Color above, dark livid brown, or olive-green, with a median 
dorsal row of about 20 to 22 bright or pale red. spots, which are 
sometimes obsolete, and a row of rounded black spots near each 
margin, corresponding in number and nearly in size with the 
ower surface bright or dark trig es or reddish 
iis sometimes with black spots near the ma 
Vermilion River ,—Say ; Norway, Maine; in aati? lakes and 
streams in other parts of Maine; and in streams and ponds near 
New Haven,—A. E. Verrill ; Minne sota,—Dr. Lei 
This species is very common and widely diffused in the fresh- 
waters of the northern United States. Its range northward 
and southward is unknown. It is the only true blood-sucking 
leech known to me from the Atlantic States. It is capable of 
drawing blood from the human skin, but ordinarily subsists 
upon frogs and tadpoles. It often attaches itself to the a _ 
por _speedily kills them, even when of large size. It 1 
ntly used instead of the imported leeches by shi palabicte 
des is equally efficaciou 
The following species, iri I have not seen, have been 
described from North America: 
Hirudo ornata Ebrard, Rone. Monog. Sangs., p. 55. North- 
western America. 
Hirudo ¢) Costaricensis Grube and Cirs.; Diesing, op. cit., p. 
509. Costarica,—CErsted. 
Mirudo Billberghi Kinberg, op. cit., p. 356, 1867. Montevideo. 
This species is described as having eight ocelli, with the genital 
ba in the 28th segment. It probably belongs to some 
other us. 
Oxyptychus striatus Grube, Fam. d’Annel., . 110, 148; Dies- 
ing, op. cit, p. 510. Montevideo,—Burmeister. 
Centr tropygu s Jocensis Grube and (CErst., 1857 Dies., op. cit., 
p- 511. St. Joce, Central America, —CErste 
SCIENTIFIC INTELLIGENCE. 
I CHEMISTRY AND Puysics. 
pesca while the solution was “hath warm, tufts of splendid 
bronze-green dichroic crystals began to 
the Beabce: These pore coliooted, and dried at 100°. By tran 
