1894.] Schulze’s System of Descriptive Terms. 371 
tre “centrad ” or “ proximad,” those lying away from the cen- 
tre “distal” or “ distad,” parts external or on the periphery 
“distan.” Any part at right angles to the imaginary radii of 
the body or to the surface, he proposes to call “ tangential ” 
as long as they are external or “ paratangential,” when they 
are internal. Thus there may be tangential parts or distan, 
distal, proximal and central, paratangential parts, and they 
may be distal from the centrum or proximal when not central 
or centran. 3 
Professor Simon Gage of Cornell in a letter to Dr. Wilder 
comments upon the use of “centran” as follows. “One of 
Schulze’s principal points over what is ordinarily given is the 
suggestion of the termination “an” for the absolute centre, 
ventral surface, dorsal surface or aspect, ete. Barclay in his 
book, pp. 168-173, considers this and uses for this purpose the 
ending “en” as “ centren, dorsen, dextren, sinistren, ” etc. 
“The natural development of these ideas would have been 
to make a distinction between internal and external, using the 
termination “an” for internal parts which are centran or 
axian and leaving “en” for the designation of such as are 
peripheral. It is, however, evident as suggested by Dr. Wilder, 
that the termination “en” is more suitable for the designation 
of internal parts, on account of its derivation and common 
use, whereas “an” is in line with the terminations “ al, ” “ad” 
and not in conflict with usage. It seems to me that Schulze is 
not wholly consistent in his use of the termination “an,” and 
that following Wilder’s suggestion, it would be much better to 
Say centren and use centran for any external points which 
might be established in the polar axis of the body.” 
The class of bodies referred to as Synstigmen are to be found 
exclusively among Protozoa or their corresponding cellular 
elements among Metazoa, and Schulze’s term is defective in 
that it takes no notice of the large numbers, especially among 
Infusoria, which have a spiriform arrangement of parts or of 
the entire body, often also more or less complicated with 
ilateral asymmetry. 
Although it is obviously desirable that the assumption of 
an imaginary centre should be made in cases which have no 
