430 MR. P. H. GOSSE ON THE STRUCTURE, FUNCTIONS, AND HOMOLOGIES 
forms a broad laminar dilatation, down which run several carinse, or ridges, of solid 
material ; the interspaces, apparently, being filled with membrane, or softer and more 
fleshy substance (c). The ridges enclose three areas, of which the central one extends 
through the whole length of the manubrium, and the two external ones are smaller, 
and compose the dilatation. This structure is worthy of notice, since it is highly 
characteristic ; and, as we shall presently find, will help us to identify this organ under 
very modified forms. 
46. The parietes of the mastax are much thinner than in Brachionus. A stout 
muscle {j) embraces the articulation of the malleus, including a portion of the manu- 
brium, and of the uncus. In E. hipposideros, a fan-shaped muscular band spreads 
along the interior side of both these parts, filling the angle, and stretching from one 
to the other : it is evidently a powerful Jlexor. 
47 . In this genus we see a structure of the incus, which prevails extensively in the 
class: each ramus is produced into an angular projection on either side of the ful- 
crum. To this projection, which I shall call alula ( 0 ), a muscular band is fastened, 
which passes down, and is inserted into the fundus of the mastax. Another more 
slender band or ligament connects the projection with the foot of the fulcrum. 
48. The tube of the buccal funnel {m) is very wide. The oesophagus (p) is also 
wide, and short. On the latter duct are seated two globose clear salivary glands {n), 
each of which encloses a spherical nucleated nucleus. These must not be confounded 
with the pancreatic glands, which are much larger, and seated on the stomach, below 
the entrance of the oesophagus. 
49. In Notommata aurita (figs. 16 to 21), while there is much resemblance to Eu- 
chlanis, the structure is in some respects peculiar. The form of the mastax is prolate, 
the longitudinal diameter exceeding the transverse, — a figure which is dependent on 
the fact, that the fulcrum of the incus, and the manubria of the mallei, are greatly 
produced in length, and are all extended nearly in the same direction ; viz. that of 
the longitudinal axis of the body (see figs. 16 & 17 )- 
50. The manubrium, as in Euchlanis, is three-looped, and dilated at the summit, 
unsym metrically (see fig. 20). The uncus is broad, composed of five fingers, which 
are somewhat divergent, and is arched transversely as well as longitudinally. It is 
furnished, on that side which is next to the dorsum, with a peculiar, semicrescentic 
process {q), strengthened by a carina: the points of these two processes are opposed 
to each other at their tips, beyond the tips of the rami of the incus. 
51. The fulcrum of the incus, when viewed ventrally, might be mistaken for a 
straight slender rod, with a round, dilated foot (fig. 16). It really consists of two 
slender curved rods, united by a thin lamina : the exterior of these, which is dilated 
laterally at the foot, is more curved than the interior, whose extremity it receives in 
the hollow of its own (fig. 17 ), as the chord of a bow joins the extremity of the arc. 
The summit of the fulcrum is obliquely truncate, and to this oblique surface are arti- 
culated, by a hinge-joint, the two rami. 
