4 
Huxley on Lacinularia socialis. 
The general nature of the pharyngeal bulb and of its 
movements has been so often described that it is needless 
for me to refer to the subject here. With regard to the teeth, 
however, what I have seen is considerably at variance with 
the accounts of both Ehrenberg and Dujardin ; the former 
calls the teeth of Lacinularia " reihenzahnigen," that is, 
having a stirrup-like frame, with many teeth set upon it ; 
and the latter, in his general definition of the " Melicertiens," 
under which head he places Lacinularia, has " machoires en 
etrier" ('Hist. Nat. des Infusoires,' p. 612).* 
As I have seen it (fig. 6), the armature of the pharyngeal 
bulb in this species — as in Stephanoceros — is composed of 
four separate pieces. Two of these (which form the incus 
of Mr. Gosse) are elongated triangular prisms,t applied 
together by their flat inner faces ; the upper faces are rather 
concave, while the outer faces are convex, and upon these 
the two other pieces (the mallei of Mr. Gosse) are articulated. 
These last are elongated — concave internally, convex ex- 
ternally — and present two clear spaces in their interior ; 
from their inner surface a thin curved plate projects inwards. 
At its anterior extremity this plate is brownish, and divided 
into five or six hard teeth, with slightly enlarged extremities. 
Posteriorly the divisions become less and less distinct, and 
the plate takes quite the appearance of the rest of the piece. 
This is essentially the same structure as that of the teeth 
of Notommata, described by Mr. Dalrymple (' Phil. Trans,' 
1849), and by Mr. Gosse (on the Anatomy of Notommata 
aurita, Mic. Trans. 1851), and very different from the true 
" stirrup-shaped " armature. 
A narrow oesophagus passes directly downwards from the 
]30sterior part of the cavity of the pharyngeal bulb, through 
the neck of the animal to the body, where it opens into the 
wide alimentary canal. 
Tliis is divided into three portions by an upper, a middle, 
and a lower constriction. 
The two upper parts are often not very distinctly divided. 
A wide oval or pyriform sac, whose wall contains many nu- 
cleated cells, opens into the upper portion on each side. This 
is the " pancreatic sac of Ehrenberg. J 
The middle dilatation frequently gives origin to several short 
cellular cceca. 
The lowest dilatation is globular, and has also several cel- 
* Leydig also finds Ehrenberg's figures " untrue to nature." 
f Not described by Leydig. 
X According to Leydig there are four of these bodies, two smaller and two 
larger, and they do not open into the alimentary canal. — Loc. cit., p. 463. 
