=. On the markings of the Carapar of Crabs. “ 
Teeth of the antero-lateral margin.—The teetly of the margin 
are normally five in number, commencing with the post-orbital | 
rst. These five are represented in figure 1, and are desig- | 
nated in order by the different letters of the word dentes (or dents 
in French) D, E, N, T, 8. Each tooth is often separated from 
the adjoining by a minute suture at the bottom of the indentation 
between them, and hence the letters always mark rather a lobe 
of the margin than simply a tooth. These teeth vary by obso- 
ghee or subdivision, like the areolets. 
obsolescence, the tooth E (second) is the first disappear, i 
this reducing the apparent number to four. Then N fades out, “8 
eaving S alone which may also be wanting. Again s es 
is sometimes smaller than 'T and even disappears. 
In the multiplication of teeth, there is often, asa addition, a 
tooth s’ (or two s’, s’’,) posterior to S. 1ere is often also a 
tooth (d’) between D and E on a lower level she D. But the 
multiplication is generally dependent on the subdivision of the 
normal tee in addition sometimes to 8 and D,—each 
of these teeth consisting of two or three teeth, either all equal or 
one more prominent. In order to determine the normal relations 
of the teeth when the number is large, we have a guide in the are- 
olets adjoining when they exist; for the areolet 4L (or the range 
, 4L,) terminates against tooth or lobe T, having about 
the same breadth that be longs to this lobe, the depression gore 
to 4L corresponding to the fissure between Nand T. So L (or 
3L, 2L) gives the breadth of the normal tooth or lobe N ; fe IL, 
when present, that of E. We thus find that usually when there 
are seven teeth anterior to S, each E, N, T, are doubled; when 
eight E, N are doubled, and either 7-18 trebled, or both T and D 
are doubled. 
The medial and antero-lateral areolets may be viewed relatively 
in two ways. If we compare the medial region as a whole wit 
either antero-lateral as a whole we find a resemblance in general 
form and subdivisions. Again we observe that the Bis ; 
areolets 4L, 5L, 6L, 3M or 4M form a transverse zone across the 
See 
zone. ‘These zones are often very distinctly brought out. ‘he 
lobes E and N are often a little posterior to the areolets adjoining, 
—or, the line of the lobe and these areolets has a direction a little 
obliquely backward of a straight transverse line. Again, when the — 
posterior prominent transverse line ne from the limit between T 
and S$ inward, anterior to 5L and not to 4L, as alluded to on the — 
preceding page, the apparent zones are nearly straight transverse. 
The medial region in the Cancer group is usually narrower 
than the breadth measured between the outer angles of the orbits: 
but in the genus Cancer of Leach ns M. Edwards), 
