Nos. 455-456.] 



HEAD OF BLATTA. 



779 



As early as 1839, Newport discussed this question 

 erable detail. lie believed in the "correctness of tlu 

 advanced by Savigny and others, that the organs ot in, 

 are the properly articulated members ol distinct si.^i 

 are perfectly analogous to the pioper oigan^ oi Inuunoti 

 attributed the conflict of views to a " too c\c 1um\c ^ .\. 

 of the head in perfect insects, without ivtciviuv lo 

 sponding parts in the larva. ' 



It was thuseaih realized that it is t.. iIk .)iU..^uu 

 that^xe must appeal foi a settlement ol tlu (|U.sI„mi 

 tunateh \eup<.i t chose as the basis ot Ins stu.U Hi 

 Muscci .omitona, x foim so highU spcciah/id as to Ik 

 for this purpose. His evidence regarding tin. possible 

 of a fifth segment must therefore be uj^etal. ih 

 his conclusion that there were at least foui stgmuils u 

 his acceptance of the cnteiion pioposed b\ ha\ ign> 



Zaddach ('54), believed that six segments 

 compositi(m of the head. Of these the hi si \v.i> 

 while the third was the second antcnnal sl^iik lU. Hi 

 regarding the presence of the lattei, howcALi, w is )c 

 the ernmeous c(mclusion that m the phl).^anKls t 

 antenncc lepiesented the second pan ot the Ciustatui 

 they were later rei)laced by the dehnitiM aniuma. ot 

 which corresponded to the antennules ot tht (. lustace. 



In 1858 Iluxlev also discussed the moottd quL-iioi 

 view point of embiyolog) With uiaKUtui^tu tho^ 

 and penetration he not onU tieatul ot thLun )i\o 

 insect, Aphis, but compared its ..UnelopniuU uiHi t ^ > 

 tacea and Aiachnida (xrantm^ th it th. pu^.uu. 

 appendages was indicative ot an eciual nmiiKi 

 argues that the absence of the appuida.^e- < "^^ 

 imply the absence of the .segnu nt. ' ' I 



it is so in the abdommal and thorac u u ,^i-mis.^ < 

 proposes the hypothesis "that m tht ituu 1^^^^^ 

 normally composed of six somites, w ' ^ 

 only m Podopthalmia, Stoniapoda, an( -"^^ 

 while in other Crustacea some < »ne < )i ^ni' 'i^^ | ^^^^^ ^ 



