ox THE DEVELOPMENT OF LTMULUS LOXGTSPIN'A. 



93 



more nearly vehieà to LimuJun than tlie Trilohita are; but T venture to 

 doubt the correctness of this view : my conchisions as set forth above 

 point in just the opposite direction. 



Lateral eyes 



ARACHXTDA 



many, simple 



]Mediari eves 



The distal portion 

 of the amhulatory 

 api^endas^e from the 

 carpopoclite consists 

 of 



Yolk in the emlirvo 

 remains long' and 

 aljiindant in 



Oœlomie cnTÏtv 



two (paired) 



four secrmonts 



the posterior region 

 of the body 



LTMULUS 



riîUsTACEA 



two, componnd two, compound 



two (paired) 



three se^-ments (in 

 the last pair, four) 



the antei'ior rej^'ion 

 of the body 



one pair m every 

 seo-ment and enters 

 into the appendao^o 



Malpig-liian tube 



Brain and optic 

 "rançlia ai'iso from 



Xanplius sta^e 



Breathe 



Oric^nsof mesoderm 

 of the ventrnm 



Blood vessel en- 

 sheatlies the ner- 

 vous system 



Entosternite 



present 



paired grooves in 

 the paired epiblastio 

 thickening's 



wantiuLC 



does not enter into 

 tlie appendage and 

 is not developed in 

 some seo'ments. 



wanting: 



one (unpaired) 



three segments 



the anterior region 

 of the body 



does not enter into 

 the appendage and 

 is not developed in 

 some segments 



wanting 



paired grooves in 

 t)ie paired epiblastic 

 thickenings 



paii'ed epil.>lastic 

 thickenins's 



wanting 



in water 



two (in spiders) 



two 



Facial suture 



present 



indistiîict 



present^ 



present 



most of them in 

 water 



in most of them not 



wanting 



distinct at 

 drirsal 'side 



the 



distinct at the mar- 

 gin 



Tlie name Gi/jaiifo>^trara may conveniently be retained for the new 

 and somewhat restricted class contai niuu' Limulii.'^ and the Trilobita. 

 The ^lerostomata excluded from the group (Miglit, in my o[)inion, to 

 be classified as an appendix to, (ir as an order of, the Arachnida. 



