I 
Kor£n and DAnIELSssEn’s: Solenopus sarsii, which attracted my at- 
tention by the great difference in size between it and other specimens 
of Neomenia and about which I wrote to Prof. DAnıELSsENn should 
eventually prove to belong to the genus Proneomenia. Prof. D. U. 
DANIELSSEN kindly informed me in answer to my inquiry that the 
spieules in the skin of Solenopus sarsii are disposed in a multiple 
layer and that moreover in this species the spicules are not all 
directed radially and with their free points emerging from the skin. 
According to a sketch kindly added by Dr. DAnıELSSEN the deeper 
layers contain spicules that are inclined at different angles, in the 
same was as it is observed in Proneomenia siuiteri. 
On the posterior end of the back, close to the extremity I noti- 
ced what appeared to be a small median opening (fig. 9) in the 
integument, barely visible to the naked eye and with weak powers 
having the appearance of fig. 10, radial folds surrounding it. Sec- 
tions prove this spot not to be an opening by which the whole of 
the integument is pierced: it only goes down half way and is here 
met by an upward outgrowth of the underlying tissue, in which 
connective tissue is especially predominant. At the top of this 
outgrowih and so at the bottom of the hole is a single layer of 
columnar epithelium (fig. 10). I cannot with certainty decide 
whether this is eiliated or not. As I find a very conspicuous nerve 
taking its course towards this integumentary prominence and ram- 
ifying when arrived in the connective tissue above mentioned, it 
appears to me very probable that this spot has some significance 
as a sense organ. The posterior ganglion of the lateral nerves 
being situated in the immediate viecinity it is very probable that the 
nerve directly originates from this. About the ultimate physiological 
function and possible homology with the olfactory organs, recently 
studied by SPENGEL (30), nothing can as yet be settled. The organ at all 
events does not appear to be subservient to any glandular secretion. 
Lastly I must not leave unmentioned the fact of my having de- 
tected in different places, more especially towards the hinder extre- 
mity of the body, what appear to be local ingrowths from the cel- 
lular integumentary layer. | can assign no special function to 
