de Man in the Dutch species, reaches a iittle way into the lumen 
of the intestine. The vulva is forming a broad transverse fissure; the 
female organ is single and extends forward in the animal. Uterus 
contains never more than one egg, which is very large and cylindri- 
form; in a female of the length of nearly 2 mm it measures 165 M 
in length. The tail relatively a Iittle longer than in the former 
described species tapers evenly, ending with its apex rounded and 
a Iittle dilated with a distinet duet for the caudal giands. 
All the specimens collected are feraales. 
Zeiss Ok ularm i k rom. Obj. C. O c. 2. 
Length 270 = 1,8 mm. 
Pharyngeal cavity: 8. 
Oesophagus 70. 
Vulva 160. 
Tail 20. 
Width 4. 
The formula of de Man gives: a = 67, /9 = 8, y = 13 1 /2. 
Diplo gaster rivalis Leydig. 
1873. Butschli, p. 120. T. XI. fig. 68. 
1876. — p. 371. T. XXIII. fig. 5 a—b, and XXIV. 
fig. 5 c. 
1884. De Man, p. 86. T. XII. fig. 50. 
1886. Orley, p. 42. 
It was taken at Ordrup Mose, behind Christiansholm, in a 
Iittle pool filled with Conferves. I got, both male and female, the 
latter with large and lively young*. The species appears to have 
no wide distribution in this country. 
Diplogaster lictor Bastian. 
1865. Bastian, p. 116. PI. X. fig. 171 —173. 
1884. I)e Man, p. 88. T. XIII. fig. 51. 
A male was taken at Lynæs, the length of which measures 
1,2 mm. 
