ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 403 



horseshoe-shaped. The nerve-fibres of the cornua of the ganglion are 

 traversed pretty regularly by ganglionic cells. The fluid in the cavity 

 does not coagulate on the addition of chemical reagents, contains no 

 morphological elements, and is connected with the body-cavity. The 

 mode of distribution of the tentacular nerves is described in some detail. 

 Direct continuations of the central fibrous mass, in the form of two 

 nerves, innervate the lower part of the body ; the hinder part is supplied 

 by a large number of nerves, the distribution of which in the body-wall 

 could not be followed far. 



New Genus of Bryozoa.* — Under the name of Delagia chsetopteri, 



M. J. Joyeux-Laffuie describes a new and curious Bryozuan, which lives 

 on and in the internal wall of the tube of Chsetopterus. It is ectoproctous, 

 gymnolaematous, and stenosomatous, and may be placed among the 

 group Stolonifera of Ehlers. It belongs to the division Orthonemida 

 of Hincks ; its stolons recall somewhat those of Cylindroecium, 

 Victorella, Avenella, or even BusTcia. In the arrangement of the zocecia 

 we find some points in common with what is observed in some species of 

 Bowerbankia ; but a quite special character is given to these zooacia by 

 the large and apparently spherical vesicle which is found on either side, 

 a little below their orifice. The whole colony is protected by a 

 chitinous and transparent ectocyst. 



Polyzoa of Victoria.")" — Mr. P. H. MacGillivray continues to publish 

 in the decades of the Prodromus of the Zoology of Victoria figures of 

 Polyzoa ; among those lately figured are Maplestonia cirrata, Amphi- 

 blestrum albispinum, Caberea rudis, C. glabra, and Schizoporella ridleyi. 



Arthropoda. 



a. Insecta. 



Nerve- Centres and Sensory Organs of Articulata.J— M. H. Vial- 

 lanes commences his fifth memoir with an account of the brain of the 

 Field Cricket (CEdipoda cserulescens and Calopterus italicus). 



Dividing, as before, the brain into protocerebrum, deutocerebrum, 

 and tritocerebrum, he finds that the first consists of the layer of post- 

 retinal fibres, the ganglionic layer, the external chiasma, the external 

 medullary mass, the internal chiasma, the internal medullary mass, the 

 protocerebral lobes, the ocular nerves and ganglia, the pons of the 

 protocerebral lobes, and the median protocerebrum. The first five of 

 these have essentially the same constitution as in insects already 

 described. 



The internal medullary mass is formed of three capsules of dotted 

 substance, covering one another, and all three are, by their internal edge, 

 closely connected with the protocerebral lobes. A direct union is 

 established by the commissural cord between the right and left halves. 



The two protocerebral lobes fuse with one another in the median 

 line, but only anteriorly and posteriorly ; the space between them is part 

 of the median protocerebrum. These lobes are formed of dotted sub- 

 stance invested over a large part of their surface by ganglionic cells. 



Immediately behind each of the three ocelli there is a small ocellar 

 ganglion, and from each of these a long ocellar nerve is given off. The 



* Comptes Kenrlus, cvi. (18S8) pp. 620-3. 



t Natural History of Victoria. Prodromus of Zoology, Decades xiii. (1886) and 

 xiv. (1887). J Aim. Soi. Nat., iv. (1887) pp. 1-120 (6 pis.). 



2 f 2 



