wer 
<a ; 
108 Tue Microscope. 
(Polygordius, Protodrilus, and Saccocirrus) have recently 
acquired great prominence as they are to be regarded as the 
modern representatives of the ancestors of the more common 
cheetopods. They have been studied principally by Hatschek, 
a Hungarian naturalist, who described a segmental organ as 
existing in the head. Recently Fraipont, who has been study- 
ing at the zoological station at Naples, has shown that this head- 
kidney does not communicate with the ccelom and that the fun- 
nel of Hatschek is but a membrane supported on slender tubes. 
This structure is shown to be exactly comparable to that exist- 
ing in ZcAhiurus and furnishes another reason for removing that 
genus from the Gephyreans and placing it among the Annelids. 
The comparison is also suggested that the larger nephridial tube 
and the smaller supporting czecal tubes are the representatives 
of the larger and smaller canals of the so-called water-vascular 
systems of rotifers and plathelminths. 
The Sucking-pharynx« of Arachnids—Within a few years 
the spiders and their allies have been recognized as very impor- 
tant from a systematic standpoint and their anatomy has been 
carefully investigated by several students. Among theseis Dr. 
J. MacLeod who in a recent paper describes (Bull. Acad. Belg. 
ILI, viii, 377) a sucking portion in the pharynx anterior to the 
passage of the cesophagus between the cesophageal commissures 
of the nervous system. This is best developed in the scorpions 
where the system of radial and circular muscles is well deyel- 
oped. It also exists in a rudimentary condition in the true spi- 
ders which, as is well known, are provided with a sucking stom- 
ach. The sucking pharynx is most rudimentary in the false- 
scorpions ( Chelifer). Mr. MacLeod also shows that there is a 
coxal gland in the harvest-men (Phalangids) and instances a 
case of hermaphroditism in the genus Zrombidium. 
Origin of Nerves—Professor Kélliker, in the course of an 
article on Histological Studies on Batrachia (Z. w. Z. xliii, p. 1, 
1885) throws considerable light on the origin of nerves. He 
finds that in the tails of very young tadpoles a few nerve fila- 
ments are sent out from the neural cord to the peripheral por- 
tions of the body. These have but few branches and lack the 
medullary sheath. Soon other filaments grow out and join the 
first and more branches are formed, thus producing an anasto- 
