1897.] ` Zoologi. 441 
occur in mammals, 47 in birds, 29 in reptiles, 5 in amphibians, 98 in 
fishes, 1 in an insect, and 1 in an unknown host: 117 of the lot, are 
‘doubtful forms... The remaining 101 Stossich divides into groups: 
(1) those with a dentated fold and no median lip; (2) those with both 
dentated fold anda median lip; (3Y those with the median lip but not 
the dentated fold ; and (4) those with three simple lips. 32 of the lot 
are larval forms mostly from fishes. ` - 
The Excretory Organs and the Blood-Vascular System 
of Tetrastema grecense Bohmig.'—The small fresh-water ne- 
mertine that was first discovered by Böhmig in 1892 has since then been 
found in sufficient numbers to enable its discoverer to give a brief de- 
scription of the excreto-genital and the vascular systems. The former 
is easily recognized in compressed animals, and appears as a system of 
coiled and anastomosing tubes along each side for the whole length of 
the animal. The tubes of opposite sides do not unite, although their 
very close contact sometimes causes them to seem to do so. At the 
anterior end of the animal near the brain there is only one canal, which 
is large, coiled, and looped, and ends finally in a meshwork-like system 
of smaller canals. Nothing like it appears at the opposite end of the 
animal, Into the larger, as well as into the smaller canals, empty 
numerous fine canals, which arise from the end-organs. 
In the organs, he distinguishes three portions: (1) the terminal 
‘canals, (2) the connecting canals, and (3) the end-organs. The first 
lie mostly between the external muscle layer and the intestine, and are 
formed by cells unprovided with cilia. They connect with the exere- 
tory pores, of which there may or may not be an equal number on each 
side of the animal. In one case there were 5 pores to a side ; in another, 
6 on one, and 3 on the other side. 
The connecting canals are distinguishable from the others by their 
greater thickness and the nature of their bordening cells, which bear 
cilia. The rounded, superficially smooth end-organs are provided at 
their free ends with two (seldom only one) flame cells, and seem to be 
formed by 3-5 cells resembling those of the terminal canals in appear- 
ance. In general it may be said that they communicate with the ter- 
minal canals only through the mediumship of the connecting canals. 
Yet, a direct connection between the two has been seen. 
The vascular system consists of 3 branches, 2 lateral vessels, and a 
‘dorsal vessel. Near the brain the last communicates with the right 
*Bohmig (97). Vorlanfige Mittheilung iiber die Excretionsorgane und das 
Blutgefiissystem von Tetrastema grecense Béhmig. Zool. Anz., XX, 33-6. ` 
