6 MR. A. H. GARROD ON THE [Jan. 2. 
be a row of papille indicating the rudiments of lamine of a fifth 
power; for, when disappearing, laminee always end as rows of papillee. 
In the case of a transverse section of a quadruplicate psalterium 
(in other words, of one in which there are laminze of four powers), 
the quaternary folds being rudimentary, imagine it to be cut through 
longitudinally along the middle of its groove, and opened out in 
such a way that the outer wall forms a straight line, whilst the 
laminz depend from it ; then the appearance will be that of fig. 1.’ 
b (2 


Fig 4. 
Diagram of transverse sections of psalterium. 
This being from an actual specimen, there is a slight want of uni- 
formity at 6 and c, which is usually found to be the case. The 
lamine of each cycle, or power, gradually diminish in size laterally ; 
and it will be noticed that, though the organ is quadruplicate where 
the folds are relatively largest, the smallest laminze disappear at the 
sides. This is nearly always the case, as it is also that near the orifice 
of communication with the reticulum they are stronger than they 
are further on. 
In different genera the relative depths of the laminz which con- 
stitute the separate cycles is not always the same. The arrangement 
depicted above is the most usual, in which the secondary folds are 
about two thirds the size of the primary, a similar difference existing 
between them and the tertiary, and so on. 
Fig. 4 is from the psalterium of Gazella arabica, in which, though 
the disposition is triplicate, it is seen that the secondary laminz are 
very little larger than the papillary rows which form the tertiary 
cycle, the primary laminze being of considerable depth. The struc- 
ture in Cephalophus is the same, only that, the psalterium being 
much smaller, all the parts are much reduced in size, the lateral 
laminee especially so. In Nannotragus nigricaudatus the equally 
small psalterium is even more simple, there being but six primary 
laminze of any depth; and these are covered with peculiarly large 
and pointed papille, three more being evidently their lateral homo- 
logues, although reduced to papillary rows. The conditions are re- 
presented in figs. 2 (Cephalophus) and 3 (Nannotragus). 
