NOTES ON OLIGOCHATES. 59 
puscle of this Enchytreid I am sorry to say that my observa- 
tions throw no light. It occurs in immature and mature 
worms at all seasons of the year. It has been searched for in 
vain, either discharged into the coelomic fluid or amongst the 
tissues of the body. Nor have empty cells been found which 
could have discharged the thread. It might be suggested that 
this thread is an excretory product ; however, as far as I have 
been able to make out, it is never got rid of,—indeed, it would 
seem to be most ill adapted for passing through the compli- 
cated coils of the nephridial canal. Possibly it may be a waste 
product of harmless nature, which is allowed to remain and 
accumulate throughout life, but here also facts are wanting to 
enable us to come to any definite conclusion. 
Amongst the other Enchytreeids or the Oligochetes in gene- 
ral no products in the celomic corpuscles which could be 
compared to these threads seem to have been hitherto observed. 
Amongst the Polychetes, on the other hand, there have been 
described in Ophelia radiata ameeboid celomic corpuscles 
containing a chitinous rod! of unknown function, first noticed 
by Claparéde (5), and recently studied in great detail by Dr. 
Shaepi (11). The latter adopts the view urged by Dr. Hisig (6), 
that these rods of chitin are of the nature of an excretory 
product.? 
In the epidermis of many fish and amphibia cells have been 
described which secrete a thread-like substance. 
Perhaps the thread-cells of Myxine, described by Johannes 
Miller, Blomfield (8), and others, resemble more closely the 
thread-corpuscles of Enchytrzus hortensis than any other 
cell hitherto known, especially in the earlier stages of their 
development. But here, again, the product appears to be of 
different chemical nature, and the cells in their origin and 
situation are so different that they scarcely help us to solve 
the problem. 
1 T have found similar but longer chitinous rods in Ophelia limacina. 
2 As the thread in Enchytreus hortensis is certainly not of chitin, a 
comparison with Ophelia (even supposing the excretory nature of the rod had 
been proved) would not warrant our coming to a similar conclusion, 
