Wilder, Net^ral Te7ins. 249 



§109. CHIASMA vs. Chiasma opticum. — Meynert's chi- 

 asma nervi acustici is not retained by the German committee, 

 and even if it were there is no hkelihood of confusion with it 

 or with Camper's chiasma tendinum. The chiasma is and always 

 will be that of the optic nerves. The use of any qual- 

 ifier suggests undesirable variations like chiasma nervorum optic- 

 oriim and commissiwa optica. Furthermore, the sufficiency of 

 the unincumbered mononym is practically conceded by the Ger- 

 man committee in designating one of the subarachnoid spaces 

 2lS cistej-na cJiiasmatis \ see also His, '95, 171, line 8'. 



§1 10. THALAMUS. — This term may naturally be men- 

 tioned here. In the German list the adjective opticus is omitted, 

 and His makes the following remark ('95, 7, lines 1-3) : "Wir 

 stimmen unsererseits vollig bei, wenn das Wort Thalamus kurz- 

 weg an die Stelle von Thalamus opticus gesetzt wird." But it is 

 worthy of note that thalamus is strictly an idionym (§24), and 

 that the only valid excuse for the addition of the adjective is a 

 desire to aid the student's memory by the association with the 

 optic nerve. As a matter of fact, no case of real advantage is 

 known to me, and the frequent repetition of the adjective may 

 easily become a burden, as pointed out by me in 1888 ('88, b). 

 §r 1 1. CALLOSUM vs. corpus callosuni. — Corpus callosum 

 is the most familiar type of a large group of anatomic names. In 

 1889, including unusual synonyms, I recorded one hundred 

 neural polyonyms of which corpus constituted the initial word. 

 Ten such remain upon the German list, (viz., corpus restiforme ; 

 cp. trapezoideum ; cp. medullare ; cp. quadrigeminum ; cp. majuil- 

 lare ; cp. genicidatuni mediate ; cp. giic. laterale ; cp. pine ale ; cp. 

 callosum ; cp. stiiatuni), and their genitives are correspondingly 

 in evidence. 



§112. It must be admitted ihdX corpus callosum is rather 

 attractively sonorous. It is easily pronounced and even, like 

 quadrupedante, "runs trippingly from the tongue."^ But that is 



1 The word chias>na is discussed at some length by Hyrtl, '80, 105-106. 



"^ A similar concession has been made (Science, June, 22, 1S8S, editorial) to 

 the claims of proper names \\]i.& Johnny McWhorter which are euphonious and 

 easily remembered. 



