/I H; Anctv K. I.;iiiil)('ii. 



sioii of llic oplic clciiuMils; the eyes boeomiiig, by this means, a threc- 

 layend, instead of a two-hiyerod, structure. This fact had been 

 |)oiiile(l out previously by Patten (<}2), in a iiiore <;cii<'ral paper on 

 ilie eyes of JVlollusks and Arthropods. 



Kishinonye's paper is one of the most imjjortant among the later 

 colli ribiil ions to (he subject. V>y his observation Ihat the division 

 of the so^'inontation nneleus is accompimicd Ity a (lixision ol thc^ yolk 

 inio parts correspond ing to the nundicr (•!" th(^ products ol nuclear 

 division, he has l>een abh' to throw important lii;ht, on the segmenta- 

 tion of this class of eggs, lie also fouiul, with regard to the body 

 cavitv of the si)idcr, that the original c(eloin disappears except that 

 portion which is enclosed in the heart, constituting the lumen of that 

 organ, and in the stercoral ]X)cket ; the body-cavity of the adult 

 s))ider being a secondary ac(]uirement. The dcNclopnient of the 

 respiratory ap|)aratiis h(> assixdates Avith the lirst two pairs of 

 abdominal appendages; the; nnuaining abdominiil appendages being 

 invohcd in the fornialion of the spinning mainniilhc. 



His description of tlie origin of the anterior — or as he calls them, 

 \\\v postei-ior — median eyes agrei^s with the oi)sei'vat ions of Patten 

 and r.ocv. He descrilx'S the otluu- paii" of median eyes and the lat- 

 eral eyes as originating in simple tliickenings of the ectoderm in \\w 

 0|)tic area; a radical departure from the conditions of origin and 

 development of the so-called accesscu'v eyes as stated by Locy. 



Whil(> St. Ivemy (oO), in his excellent monogra|)h on the nervous 

 system of Artliropods, has given an accurate desci-iptiou of the condi- 

 tions in the adult brain of the spider, either on ai'count of the ditii- 

 culties presented by the problem, or for want of intcu-est in it, very 

 little work has been accomplished, in relation to th(> special ])robleTus 

 of development, on the AraiuMd brain. Neither iJalfour, Locy, nor 

 Ivishinouye, have giA-en satisfacttu-y acconuts of the origin and devel- 

 opment of the cephalic lobes. 



r>alfour found that \hc brain originates as a thickening of the 

 cephalic plate, and that it presents a segmented condition. But he 

 failed to state whether he regarded the segmentation of the cephalic 

 ])\i\\o as having any spcn^ial significance. Tie folloAved the develop- 

 ment of the brain through to its separation from thv. ectoderm, and 



