XXxiv JoiKNAL OF COMPARATIVE Np:rKOLO(;Y. 



cells. Nerves arise from the brain for the frontal organ, eyes, firt^t pair 

 of antennre and the labruni. This supra-CKsophageal ganglion is united 

 by strong connectives with the siib-oesophageal, and the connective is 

 supplied with scattered cells laterad. Nerves are given off from it to 

 the second antenna- and labrum. A number of ganglia are united in the 

 band-like sub-oesophageal mass. Three tuberosities correspond to 

 mandibles, maxillie and maxillipedes. There are regular blood sinuses 

 or lacun<e extending through the system. All the nerve cells are of the 

 multipolar type. 



The Development of the Nervous System of Si»iders.(1) 



This Japanese author has investigated especially the development of 

 the eyes, using the genera ^iffaleiia and Lycosn principally, and verifying 

 statements by comparison with T/ieridiou, Epeira, Dolomedes and 

 PholcHs. His statements conflict with those of Locy, Schimkewitch 

 and Patten in several particulars. Segmenting stages of the eggs were 

 plunged directly into hot water, while older eggs were gradually heated 

 in water to 70 or So° C. The process was continued until the eggs were 

 opaque and white. After cooling they were placed in 70 per cent, 

 alcohol and carried up to absolute gradatim. The precaution was taken 

 of examining the eggs one by one under a dissecting microscope and all 

 those in which the membrane was not burst were perforated by a 

 needle to facilitate permeation. They were stained in alcoholic 

 cochineal, picrocarmine, alcoholic carmine and hicmatox^-lin. ParatHin 

 was the imbedding agent. 



The following statements from the author's summary are germain 

 to our work: 



The brain and the ventral nerve cords are formed as a continuous 

 ectodermal thickening. The brain is composed of the semicircular 

 grooves and the lateral vesicles cut oft" from the ectoderm. Later it is 

 divided into three segments. The development of the posteinor median 

 eyes is connected with that of the brain. Their development is quite 

 difterent fronn that of the other eyes; but all the eyes are dermal 

 in origin, not neural, and the nerves of the eyes always enter from the 

 inner ends of the ectoderm cells. 



The spider's brain consists of three segments, as Patten claims. 

 From his description, Patten seems to mean that in scorpions and 

 spiders the three segments of the brain are formed from three- separate 

 invaginations; but I am unable to corroborate this statement. Moreover, 

 he says that the anterior median eyes (my posterior median) belong 

 to the second segment, while the three remaining pairs belong to 

 the third segment. Supposing that his second segment is anterior 

 to the third segment, I cannot corroborate this statement either, 



I Kamakichi Kishinouye, " On the Development of Araneina," the Journal of the 

 College of Science, Imperial University of Japan, Vol. IV, Part I, pp. 55-88, Plates XI- 

 XVI. 



