376 Cc. O. WHITMAN. 
are very abundaut in the Sawahs (rice-fields), in the water of 
the low lands around Batavia and elsewhere on the north coast 
of Java. The Malayan name is Lintah. Both varieties are 
used for medicinal purposes.” 
4. Le ptostoma.—Three species of Japanese Leeches (Pl. 
XVIII, XIX, and XX) agree with the forms hitherto men- 
tioned in having twenty-six somites between the first pair of 
eyes and the acetabulum, but differ from all of them in having 
fewer abbreviated somites. This peculiarity shows that these 
Leeches have not descended from Hirudo medicinalis, and 
that they are entitled to rank as a more primitive type than 
any of the Hirudinide at present known. These Leeches 
possess certain characters (denticles rudimentary or absent) 
that suggest relationship with Aulostoma; but Aulostoma is 
unquestionably an offshoot from Hirudo, and the characters in 
which it approaches Leptostoma cannot be regarded as evidence 
of genetic affinity. The rudimentary condition of the denti- 
cles and maxille, with all the correlated peculiarities, are 
characters that have been acquired independently by the two 
genera. Leptostoma and Hirudo, we must assume, had a 
common ancestral form; and Leptostema has departed from 
this archaic form in much the same way that Aulostoma has 
departed from Hirudo. This seems to me to be the most 
rational mode of explaining the relationship of these genera. 
Pl. XX, figs. 54 and 55, will show the more important cha- 
racters on which the new genus Leptostuma is based. These 
figures represent the two extremities of Leptostoma pi- 
grum somewhat diagrammatically. Looking first at the 
anterior end (fig. 54), we find only five abbreviated somites. 
These five somites contain the same number of annuli (10) as 
the corresponding somites in Hirudo; but there is a small dif- 
ference to be noted in the last ring of the 5th somite. This 
ring is constantly larger than the other rings, and hence it 
may be regarded as representing two rings combined. The 
6th somite includes five annuli, two more than the same 
somite in Hirudo. This difference explains other differences ; 
for instance, the position of the first pair of nephridia! pores 
