2IO 



NA TURE 



[Dec. 30, 1886 



From each prosencephalon is budded off an olfactory lobe or 

 rhinencephalon, containing a cavity, the rhinoc<ele, and usually 

 divisible into a stem like portion, or cms, and a dilated 

 extremity, or bulb. 



(e) The mesencephalon becomes differentiated dorsally into the 

 paired optic lobes, or optciicephala, the cavities of which, or 

 oploavUs, are frequciitly clearly distinguishable from the remain- 

 ing median portion of the mesocoele, or //t-<-, with which they 

 communicate by small apertures, the pyhe. In many fishes, 

 however, although the optic lobes are well formed, the mesocule 

 shows no distinction into iter and oplocoeles (cf. Fig 2, K and 

 E). The unpaired ventral portion of the mid-brain, which in the 

 lower forms shows no differentiation into crura cerebi may be 

 distinguished as the basi-opticus.^ 



{/) In the epencephalon the dorsal region grows out into the 

 cerebellum, or epencephalon proper, its ventral region, or basi- 

 cerebelluin (prre-oblongata. Wilder), being usually quite indistin- 

 guishable from the metencephalon, but becoming marked off in 

 the Mammalia by the development of the pons. The anterior 

 portion of the fourth ventricle of the adult, i.e. the portion corre- 

 sponding to the basi-cerebellum, is of cnirse epencephalic and 

 not metencephalic, and may be distinguished as the atrium 

 (Fig. I, c and D ; Fig. 2, e) : it commuijicates, in Selachians, 

 with the epicoele proper, or cerebellar ventricle, by a small aper- 

 ture, the osliuni (Fig. 2, B and E, osl.).- 



It will be noticed that a mixture of Latin and Greek names 

 occurs in the above scheme. This has been adopted so as to 

 interfere as little as possible with the names in common use and 

 with those proposed by Wilder. The Latin names, moreover, 

 are introduced with a certain consistency ; e.g. the basi-cerebrum 

 is the median unpaired portion of the protencephalon, the basi- 

 opticus of the mesencephalon, and the basi-cerebellum of the 

 epencephalon ; similarly, the cavities of these basal regions are 

 respectively the aula, the iter, and the atrium, the main 

 " ventricles" being all distinguished by names of Greek origin. 



The advantages claimed fur the proposed nomenclature are 

 the following : — 



^ (a) Names are given to important structures which have 

 hitherto been designated by more or less lengthy phrases, e.g. 

 basi-cerebrum, aula, mesoccele, &c. 



(b) The systematic brain-nomenclature of Quain is brought 

 up to date by introducing changes rendered desirable by the pro- 

 gress of animal morphology. 



{c) The cavities of the brain are distinguished by systematic 

 nnmes which have an evident connection with those of the 

 encephalomeres themselves, instead of by names which have no 

 relation either with the regions of the brain in which the cavities 

 occur, or with one another. 



(</) The de cription of the nervous system of the lower Chor- 

 data is simplified. For instance, in Amphioxits, one may say 

 that the neuron shows no distinction externally into encephalon 

 and myelon, but that the neurocrele is dilated anteriorly into a 

 small eiicephaloccele. 



While agreeing with Prof. Wdder in the advisability of making 

 the changes proposed above in the nomenclature of the central 

 nervous system, I differ from him in failing to see the necessity, 

 or, indeed, the desirability, of making all bmomial names mono- 

 mial. Such names, for instance, as anterior commissure, corpus 

 callosum, lamina terminalis, which are not misleading, and 

 which do not require to be connected with homologous parts by 

 -a consistent nomenclature, may very well be left alone ; although, 

 if one could start ab initio, I quite admit that the substitutes 

 proposed by Wilder might be preferable. In any case, how- 

 ever, his nams pseudtica-le is thoroughly deserving of adoption 

 as a substitute for the misleading appellation, "fifth ventricle." 



Prof. Wilder's suggestion that encephalon should be Anglicised 

 into encep/ialh worthy of consideration, especially as the word 

 ought to be written em/phalos, and it would be an advantage to 

 get rid of the incorrect neuter termination. I have adopted the 

 abbreviated form in the following table, which shows at a 

 glance the nature of the projiosed scheme of nomenclature. The 



to using an adjective as a substantive, but 

 ely a matter of usage," &c. (Pye-Smith, 



' Critics will no doubt obje 

 how far this is admiss.ble is en 

 Ice. cit., p. 174, note). 



^^ Cercbeliavi is one of the few names in the older brain-nomenclature 

 which presents no ambiguity, so that the only reason for giving it a Greek 

 synonym is the logical satisfaction of having a similar set of names for all the 

 great divisions of the brain. Strictly speaking, the word epencephalon, 

 being synonymous with ccrSellar segment, au)i\\l not to be used for the 

 cerebellum itselt, and ttypcrenccphalon might be used instead, with hyieroccele 

 for cerebellar ventricle. 



names of the various divisions of the nervous system are printed 

 in capitals, those of the corresponding cavities in italics. 



X g 



ChO^ 



^■3 



< 



X 



Ph 



w 

 u 



W a 



w ^ 







§1 

 ^ % 



w s 



My object in writing this note is not so much to get my own 

 or any other system of names adopted, as to urge the necessity 

 for a reform in the no;nenclature of the central nervous systetii.and 

 its cavities — a necessity which no comparative anatomist, espe- 

 cially if he be a teacher, can fail to see. Recent investigations 

 of the skull, shoulder-girdle, urinogenital organs, &c. , of Verte- 

 brates have necessitated corresponding changes in nomenclature, 

 and similar changes are constantly being made among the various 

 Invertebrate groups. It would certainly be a great boon, both 

 to teachers and students, if a like reform could be generally 

 adopted for the Vertebrate nervous system. 



Dunedin, N.Z., September 15 T. Jeffery Parker 



TNE IMPERIAL INSTITUTE 



'T'HE following is the report of the Committee appointed by 

 H.R.H. the Prince of Wales to prepare a scheme for the 

 proposed Imperial Institute : — 



The committee appointed by your Royal Highness to frame a 

 scheme for an Imperial Institute intended to commemorate the 



