110 Tue Microscope. 
cells give rise to mesoderm, notochord nervous system, ete. ; 
Did they describe the methods by which certainty was obtained, 
one could have more confidence in the results. 
The Green-gland of Crustacea.—There exists at the base of 
the second antenna in most Crustacea a peculiar gland known 
as the “ green-gland.” In the older works this was regarded as 
an ear, but more lately it has been regarded as urinary in its 
nature. This is now proved, as Mr. A. B. Griffiths (Proce. R. 6., 
XxXXviii, 1885) has extracted from it uric acid crystals. In all 
probability the gland is to be regarded as a remnant of a series 
of segmental organs of which there was one in each segment in 
the ancestral worms from which the Crustacea were derived. 
Concerning segmental organs reference may be had to the next 
note. 
Segmental Organs of an Earthworm.—Until recently it was 
believed that no worm had more thana pair of segmental organs 
in each segment, but EHisig showed that in the peculiar worms 
known as Capitellidz this member might be excluded. More 
recently Mr. F. E. Beddard (Proc. Roy. Socy., xxxvili, 1885) 
described the segmental organs in an earthworm from Australia, 
where each segment has eight segmental organs, one opening at 
the base of each seta. The seta are not arranged here as in our 
familiar earthworm but are widely separated. The exact 
explanation to be given for this anomalous condition is not read- 
ily ascertained. 
Function of the Thymus Gland—Victor Horsley (Proc. 
Roy. Soc., xxxviii, 1885) comes to the conclusion that the func- 
tion of the thymus gland is concerned in the nutrition of the 
brain, the existence of mucin in the blood, and the composition 
of the blood. Nothing accurate was known on these points 
until 1883, although it had been noticed that the extirpation of 
the gland in cases of goitre was followed by cretinism, a fact 
which naturally led to the supposition that it exercised some 
influence on the supply of blood sent to the brain. 
The Hydroid stage of Limnocodium.—Some years ago a 
medusa suddenly appeared in the tanks in which the great 
South American water-lily ( Victoria regia) was kept in the 
Kew Gardens. It of course excited no little interest, as it was 
the only fresh-water jelly-fish known. Whence it came is abso- 
