THE GENERA OF MOSSES. 
445 
time equidistant, but approximated or united in various 
degrees in the different genera and species of the section." 
As it is most desirable in every science, and especially in 
that of muscology, to have the technical terms well defined, 
and their meaning limited to their respective objects, we 
shall here explain what we hold to be signified by the 
terms, denies gemi7iati, denies geminantes, denies Jissi, and 
denies per paria approocimati *. 
The dens^ geminatus is a tooth which appears to be a 
single one, but which is marked by a longitudinal semi- 
pellucid line, denoting a tendency to separation, and often 
actually producing a separation ; the line must therefore 
extend from the apex to the very base, and might be called 
with propriety the linea separabilis. There are thus ac- 
tually two teeth, which, when united, are called a once-^^- 
minqte tooth, and, when separated, tv^o ge7m7iafing ieQih. 
The denies geminantes are a greater or less number of 
teeth longitudinally coalescing, the numbeF of teeth so 
united being shown by the semi-pellucid longitudinal striae. 
The whole is called a tooth, which is farther characterised 
by being once, or twice, or four times, geminated. 
The dens Jissus is not provided with a linea separahiUs: 
• From the confusion that has been created in consequence of the want 
of a general understanding on this point, the reader will readily concur in 
the necessity of a reformation of terms. The uncertainty of the present no- 
menclature may be exemplified in a few words. Hedwig, ScHwaeGRicHEN, 
and others, describe the teeth of a Splachnum as " S-geminati.^' Bridel, at 
first, as " S-paria^''^ and afterwards (as in S. Magdlanicum) " IQ-geminatiy 
While several authors apply " denies geminati " to Splachnum, they use the 
phrase " sedecem paria " to Systylium, and " 16 per paria approximati " to 
Zygodon and Ortkotrichum, the structure of the teeth in all being the same. 
At the same time, also, "16 paria,'' or '« 16 per paria approximati,'" are 
attributed to Didymodon, Trichostomum^ and Leucodon, genera having a 
peristome of a totally different nature. 
