344, Prof. R. Leuckart on the Developmental 
It is clear that, notwithstanding a residence probably of years 
in the mole, these animals constantly retain the embryonal 
character, and this even more rigidly than the young Ascaris 
acus, which grows in its intermediate bearer to as much as four 
times its original length. In all probability they remain in the 
mole without any alteration at all; for the above-mentioned dif- 
ference of size exists even at the time of their immigration, as 
may be readily ascertained from the specimens not unfrequently 
found in the contents of the stomach among the remains of half- 
digested earthworms and larvee of insects*. 
As regards the parentage of these worms, I can only add to 
the supposition already indicated, that they appear to have no 
genetic relationship with the sexually mature Nematode worms 
which live in the mole. It is evident that their residence in the 
mole is only temporary, and intended to facilitate their trans- 
ference into other animals. Starting from this point of view, I 
fed two young buzzards, taken from the nest, with several moles 
every day, for three weeks, and in this way most certainly trans- 
ferred many thousands of the worms into their intestines. My 
hope of seeing the worms further developed in their new hosts 
was indeed disappointed ; but, on the other hand, I found the 
lungs and liver of both the animals (especially their peripheral 
portions) sprinkled with innumerable small tubercles, each of 
which, as in the moles fed for experiment, contained a small 
roundworm. As these little worms agreed in every detail (size, 
form, and internal structure) with the above-described young 
forms, I do not hesitate to refer to the experiment made for the 
explanation of the phenomenon, and to affirm that the parasites 
in question, after their transfer into the new host, recommenced 
their migrationt, as I have already endeavoured to show is 
* The stomachal mucous membrane of the mole contains another young 
Nematode form, of 0°73 millim., with a rounded head (without a boring- 
tooth) and a caudal point, from the base of which two smaller points pro- 
ject. The internal structure shows no essential difference from that of the 
form above described; but this similarity of course does not suffice for the 
assumption of a genetic connexion. The so-called Trichine of the earth- 
worm, which occur in great quantities free in the contents of the stomach 
of the mole, have nothing to do with these worms. They are rapidly de- 
stroyed in the stomach of the mole, without any trace of further develop- 
ment. One earth-worm, however, harbours several species of Nematoda, 
and especially, besides the common so-called Anguillula (Rhabdites) lum- 
brici, which, notwithstanding its pharyngeal armature, has probably con- 
tributed most to the confusion with Trichine, two young forms with which 
T am unacquainted. 
+ With this Herbst’s statement also agrees—namely, that in his experi- 
ments with ‘‘ trichious ” moles’ flesh, in pigeons, magpies, and weasels, 
he found the worms administered in the muscles and other organs. (Nach- 
richten von der G, A, Universitat zu Gottingen, 1852, No. 12.) 
