54 Mr. F. A. Bather—Suggested - 
to formulate the laws of arm-branching in the various families 
or genera. The difficulties are of two kinds, subjective and 
objective. We will take them in that order. 
__ The subjective difficulties are due chiefly to the cumbrous, 
illogical, and, for the most part, meaningless nature of the 
terms adopted. This is not a censure of any one in _parti- 
cular, for no one man could ever have invented such a discon- 
nected lot of names for similar and connected objects. The 
terminology has grown up bit by bit, unsubjected to the stern 
laws of natural selection. It is by no means easy for the 
student, or even for the describer of new species, to carry all 
these names in his head. It is on the face of it absurd to 
begin a fresh series of numbers at the postpalmars, as though 
there were some morphological change ; moreover, the inter- 
pretation to the mind of such a phrase as “ the second post- 
palmars” involvesanarithmetical calculation before one realizes 
that the ossicles alluded to are brachials of the fifth order. 
Then, in speaking of a particular ossicle, one can hardly say 
“the second third postpalmar,” so one is obliged to indulge 
in some such cumbrous circumlocution as ‘ the second ossicle 
in the third postpalmar series.” The symbols too that are 
employed in specific formule—c, d, p, p’, p', 6, &e.—hardly 
convey their meaning at a glance, while they certainly do 
not lend themselves to the expression of statements referring 
to more than one order of brachials at a time. It is of course 
possible that these difficulties are not obvious to highly trained 
intellects, and it is true that they hardly present themselves 
in the study of most recent Crinoids. 
There is, however, a more serious objection, at least to one 
of the terms. It was J. S. Miller who invented the now 
resuscitated term ‘ costals,” and it is true that he used it to 
denote the second radials, where he did not call them arm- 
plates. But, as can be seen from the table that was given by 
Carpenter (op. cit. p. 16), he also applied the term to the first 
radials, the basals, and the infrabasals. It would no doubt have 
been legitimate to restrict the term to one or other of the plates 
to which it was applied by Miller; but unfortunately this 
had already been done. As Carpenter himself pointed out, 
Prof. Lovén has “ proposed to specialize this name as denoting 
the primary interradial plates of the Echinoderm apical 
system, 7. e. the genitals of Urchins and the basals of 
Crinoids.” It may be true that Prof. Lovén’s proposal “ has 
not been generally accepted by Echinologists;”’ at the same 
time there are others who have applied the term “ costals ”’ to 
interradially disposed plates, notably Prof. James Hall, who 
has thus denoted the basals of various species in the ‘ Palaon- 
