Boe! ' Mr. F. A. Bather— Suggested 
This system has the advantage of at once conveying to the 
mind, in the simplest possible manner, the desired ideas. _ It is 
obviously ¢apable of indefinite extension ; but, since very few 
arms branch as many as twelve times, it does not involve 
words of any great length. It is true that “ primibrachs ” 
is longer than “ costals ;”” but then “the fourth sextibrach ” 
is far shorter than “the fourth brachial of the third -post- 
palmar series ”’ or even than “ the fourth ossicle after the fifth 
axillary,” which latter is a periphrasis proposed to me by 
Mr. Wachsmuth. Besides, the system is merely a more con- 
venient rendering of terms that have been, and are still, 
employed by authors of repute, including Wachsmuth and 
Springer. Ina letter dated August d5th, 1891, Mr. Wachs- 
muth writes: “The terminology of the brachials which you 
propose is almost the same which I proposed to Carpenter 
when we discussed the question’ two years ago, with the 
exception that I called the costals ‘ primary brachials,’ the 
distichals ‘ secondary brachials.’ At first we thought these 
terms were excellent, but, using them in some of our descrip- 
tions, we found them extremely cumbreus, and this induced 
us to accept Carpenter’s terms.” He adds, however, “ we 
occasionally use primary and secondary brachials in place of 
costals and distichals as a change.” ‘The alteration involved 
in adopting the proposed system is therefore of the smallest 
possible kind, while the terms have all the ‘excellence’ 
without the ‘cumbrousness’ of those still used occasionally 
by Wachsmuth and Springer. OR 2 
A still greater advantage of: the new system is that it can 
be extended to all parallel structures. The general term at 
present applied to the covering-plates of the ventral grooves 
is “ambulacralia.” ‘This word may be conveniently short- 
ened in composition, and the various series denoted as “ prim- 
ambulacs” &c. A similar nomenclature can be applied to 
cirrus-ossicles or “ cirrals,” and to root-ossicles or “ radicals,” 
in cases where these branch. 
The supplementary plates that occur in some Camerata 
between the secundibrachs and tertiobrachs of a single ray 
have been called “ Interdistichals”’ and “ Interpalmars.” 
The change to ‘¢ Intersecundibrachs ” and “ Intertertiobrachs ” 
is hardly euphonious ; but there is rarely occasion to use these 
terms. ‘lhe corresponding plates of the ventral surface should 
of course be known as ‘ Intersecundambulaes ”’ and * Inter- 
tertambulacs:” these plates: have‘ hitherto had no distinctive 
names, and some may think that it was better so. 
As yet we have only considered the proposed system in its 
application to simple or non-pinnulate arms, when those are 
