Mi:M<HliS OF TllK .NATIONAL ACADEMY OF S( IK.NCKS. 309 



laifit' ;;;iii;;li<iii. vi/. the nnrniul f;;iiiKlioii cflLs, in \vbi(^h tlio iiiiclcu.s is siirnniiuh'd by an abiiiidiuit 

 l.rot.iplaMn. 



It sliiiiilil mIsi) b(> ohscrvi'il tliat tlic niuslinioni Ixxlics arc lii'st (h'vi-lopiMl in atlnlt insects, and 

 t's|KHMally in thnso ofa lii;;li ih';L;n'i" orintellitfence. Now Liniuhis is low in tiic plane of intclli- 

 {jence. It bnnows in the mini and in a hapliazard way devours wliate\(i worms and otlier soft 

 bodied animals it can obtain with its spiny based legs. 



On tlie other hand we were, before leadinjj Viallaiie's llnal memoir, inclined to homolo{i;ize the 

 '•nucleofienns bodies" of Limubis in part with the cortical masses of chromatic <ells tigtired by 

 Saint Uemy (Figs, xii and xni I. ol.) which envelop the optic lobes of s]>iders and the cerebral 

 lobes of the scorpion (Fig. xiv a. ganij. ;«.). 



Whether a peduncula^d body is i)reseut in tiie brain of myrio|)ods apjiears from tiie carefnl 

 researches of Saint lieuiy to be a ma"tter of doubt. He does not seem to have detectiil any organs 

 like them in the genera he investigated except in Julns, where he obseived some vestiges which he 

 compares to the pediunrulated bodies of insects. In Scutigera (Cermatia) he discovered what he 

 doubtfully liomologizes with the pedunculated bodies of in.sects, remarking a.s follows: 



Th« liomolugii's of tlie coiiipluiiited apparatus that we have .just described are difliciilt— we may even say 

 iiii]iossil>lc — toestalilisli with i-ertaiiity. The general aspeot and the disposition of the prinei]>al parts leads one at 

 lirst to think that this ensemUle represents the pedunculated body so constant in inseets and the vestiges of which 

 wi- have found in Julns. Hut when wo examine the thing more closely ,and push the comparison more thoroughly 

 we immediately ])ereeive that the resemblance is absolutely superficial and that wo can not tind points of precise 

 ri'semblance between the i)ortious of our apparatus and tliose of the pedunculated body of insects. We are here 

 even less well informed tlian in Julus because there are wanting the relations with the optic lobe (commissures of 

 Hellouei^ which have serveil as in this case to affirm the existcuce of a rudimentary pedunculated body represented 

 by a calyx. 



From the lack of facts of this kind it must be acknowledged that we have to content ourselves with hypotheses, 

 though quite plausible ones. Without seeking to compare these organs in their details, we shall regard them as 

 very probably honndogues. What are, indeed, the constituent parts of the pedunculated body of insects? An 

 ai'cumulatiou of chromatic cells in relation with a system of medullary stalks which are planted in the proto- 

 cerebron, and end abruptly in the midst (nii seiii) of the punctuated substance. Wo shall iind the same structure 

 and the same arrangements in the pedunculated organs of Scutigera. The peduncles end near the median line, as 

 does the be.am (trabecula), and the internal tubercle ends near the neurilenuna, as the anterior horn in these last. 

 The thin ganglionic ma.sses seem to play, opposite these parts, the same role as the ealices opposite (vig-u-rin) the 

 horn and the beam (j)Oulre) (pp. 74, 75). 



In Peripatu.s also Saint Remy describes and tigures a system of plates and a medullary mass 

 perhaps comparable to the pedunculated orgau of Scutigera, as he states on i). 242 : 



Ce syst^me des lames et de la ma.sse mi5du11aire pent 6tre company a I'organo pddoncuW de la Scntigi^re. Ici 

 cimime chez la .Sciitig<"'re, nous avons un organe m^dullaire qui recueille, d'uno part, les prolongemeuts de petites 

 cellules chromatiques jtanvres en protoplasma, et est en relation, d'outre part, avec des pieces qui s'enfoncent dans 

 la snbstance ponctm^o et se termineut franc'hement sans contractor' de rapports a I'extremitc^ avec d'antres rf^gions. 

 JIais. outre ce rapprochment fondi? exclusivement sur des caractferes geueraux, il est possible d'en faire un autre avec 

 le corps p^donculd des insectes, bas<^ sur les memos carac;tere8 et appuyd de plus sur un fait anatomiqne iuterrcssant. 

 lexistence de relations entre ees organs et le lobe olfactif, ain.si que la region qui donne naissance an pddiculc 

 nptique, disjiosition commune a I'organe que nous v^uons d'etndier chez le P<5ripate <^t an corps pedoncnld des 

 iii.sectes. 



Under the circumstances, then, we were at first unable to agree with M. Viallanes that 

 what he regards as pedunculated bodies are really such, nor did they appear to be the homologues 

 of the problematical organs in the brain of Onychophora (Perii)atus), or of Myriopoda. Further 

 and very extended examination of the brain of young Linuili after their first molt, and when 

 they are less than an inch long, exclusive of the caudal spine, are urgently needed to linally settle 

 this and other difficult points in the homologies of the brain of Limulus. 



X. COMPARISON OF THE BRAIN OF LIMULUS WITH THAT OF ARACHNIDA. 



Thanks to the able and very detailed account and beautiful figures of Dr. Saint Hemy, we 

 now have a means or standard of comparison in studying the brain of Limulus which has not 

 hitherto been afforded us, and which have greatly aided us in coming to a better appreciation of 

 tlie nature of the brain of Limulus. There seems little doubt but that the brain in (luestion is in 

 its general features much like that of Araclmida. This is largely owing to the similarity in the 



