9 
the walls of separation being scarcely elevated from the surface. With the 
exception of two small fossae seen to left of the orifice, and three larger below 
towards the csecal extremity of the gut, the entire mucous membrane, both 
within and without the pouches, is beset with follicles having precisely the 
same character as those of the last Peyerian patch within the small intestine. 
Some few of the sacculi are subdivided by secondary lamellae ; but, generally 
speaking, these are not very prominent. The larger folds are extremely 
thin-walled, transparent, and extensile, so that the amount of secreting tissue 
becomes much greater than is at first sight apparent ; in one example, to the 
left of the figure, the orifice of the sacculus is much contracted, while the 
cavity, on the other hand, is particularly capacious. Altogether, without taking 
into consideration the laminae, the follicular structure covers a space equal to 
about two square inches. 
In a young Giraffe more recently dissected, I found this curious develop- 
ment still more complicated. In this case there were at least twenty cir- 
cumscribed fossae. Ten exhibited very small outlets, and two or three of the 
larger and more patent pouches displayed secondary sacs in their interior.* 
A few of the Peyerian glands occupying the small intestine also display a 
tendency to this folding, and afford a consequent increase of the secreting 
element. This was especially marked in the younger Giraffe just alluded to ; 
but in the other animal the folds were also present, consisting of semilunar 
valve-like productions, forming a kind of hood overlapping the duodenal end 
of each patch. This is well shown in fig. 3, where the concavity of the hood 
is seen to be capable of admitting the tip of the little finger. 
Fig. 3. 
One of the ordinary compound or Peyerian Glands of the Giraffe, showing a 
valvular hood-like fold at the duodenal end. Natural size. (Original.) 
* See ‘Proceedings of Zoological Society’ for February 1860, where full 
references are given to other original Memoirs in connection with this subject. 
