52 Journal of Comparative Neurology. 



by four of the older American neurologists, C. K. Mills ('97), Henry 

 F. Osborn ('82, '84, '88), E. C. Spitzka ('81, '84), and R. Ramsay 

 Wright ('84, '85); and unreservedly by eight of the younger, W. 

 Browning, T. E. Clark, P. A. Fish, Mrs. S. P. Gage, O. D. Hum- 

 phrey, B. F. Kingsbury, T. B. Stowell, and B. B. Stroud. (9). 

 Coelia and its compounds are idionyms, i. e., used in no other 

 sense in normal vertebrate anatomy ; hence, unlike ventriculus 

 and its compounds, they are free of ambiguity. This argument is 

 stated last because it seems to the committee of comparatively slight 

 importance. Theoretically, of course, ventriculus (encephali) might 

 be mistaken for ventriculus (cardiac s. cordis). Practically, however, 

 the context would almost infallibly obviate misapprehension. Hence 

 the absolute unambiguity of coelia and its compounds would not in 

 itself justify its replacement of ventriculus. It would be a causa vera, 

 but hardly a causa sufficiens. 



The special arguments for the adoption of mesocoelia in advance 

 of the other coelian compounds are four : 



(i). There is substantial agreement among anatomists in recog- 

 nizing a definite encephalic segment under the title mesencephalon ; 

 this cannot yet be said of the other regions. 



(2). The cavity of this segment has no common ventricular des- 

 signation like " quartus," "tertius," and "laterahs." 



(3). The terms, ventriculus mesencephali or v. mesencephalicus 

 (English, mesencephalic ventricle or cavity), are seldom used and are 

 somewhat clumsy. Even less convenient are the phrases "aquaeductus 

 cerebri Sylvii " and " iter a tertio ad quartum ventriculum." 



(4). The abbreviations, iter and aqueduct, while sufficiently de- 

 scriptive of the adult conditions in man and other mammals, are quite 

 inappropriate to the "vast and spacious cavity" of the embryonic 

 mesencephalon, and to the lateral extensions in frogs, reptile^, and 

 birds. 



Sections C and D of the Report give the Hsts of names of bones 

 and muscles recommended by the committee, which are identical with 

 those in the B. N. A. and of those which differ from those of the B. 

 N. A. For these lists consult the full Proceedings of the Association. ^ 



D. S. Lamb, Secretary. 



'Also the Philadelphia Medical Journal, Feb. 25, 1899. Copies of the Re- 

 port will be mailed upon application to the secretary of the committee. Dr. B. 

 G. Wilder, Ithaca, N. Y. 



