A STUDY Iff MORPHOLOGY. 
79 
During the first Protozoea stage (Plate 3, figs. 28 and 29) it has only one denticle, 
which is large and pointed, and situated at the posterior angle of the cutting edge ; but 
at the second Protozoea stage (Plate 4, fig. 37) a number of smaller denticles have 
appeared in front of the long one. The mandibles are never quite symmetrical, but 
the outline of the left always differs a little from that of the right. 
The external surface of the first maxilla of the first Protozoea is shown in fig. 30, 
and the posterior surface of that of the second Protozoea in Plate 4, fig. 38. It 
consists, at both stages, of a basal portion made up of two joints with cutting hairs 
(fig. 38, i and 2 ); a two-jointed endopodite (en), with three long slender hairs; and an 
exopodite or scaphognathite (figs. 30 and 38 sc), with three long slender hairs. In 
the first stage (fig. 30) the hairs of the scaphognathite are simple, but in the second 
stage (fig. 38) they are plumose. 
The posterior surface of the second maxilla of the first Protozoea is shown in Plate 
3, fig. 31, and that of the second Protozoea in Plate 4, fig. 39. It consists of a 
many-jointed basal portion (6), a two-jointed endopodite (en), and a scaphognathite or 
exopodite (sc). The whole inner edge of the appendage carries short stout hairs; the 
tip of the endopodite a few somewhat longer hairs ; and the scaphognathite three 
slender plumose hairs, which are much longer in the second than in the first stage. 
The first maxilliped (figs. 32 and 40) is very similar to the second antenna, and 
consists of a two-jointed basal portion, a four-jointed endopodite, and an unjointed 
exopodite. The inner edge is set with short stout hairs, which are simple in the 
first, but irregularly plumose in the second Protozoea stage. The terminal joint of the 
endopodite”carries four long slender simple hairs, and the tip of the exopodite four 
long straight slender hairs, which are plain in the first but regularly plumose in the 
second stage. 
The second maxilliped of the first Protozoea is shown in fig. 33, and that of the 
second Protozoea in fig. 41. It is essentially like the first maxilliped in structure, but 
much smaller, and apparently of little functional importance. 
In the second stage there is a small convoluted shell gland (fig. 35, sg), which 
appears to open at the base of the first maxilla; but the constant and violent 
movements of the limbs render it difficult to decide with confidence exactly what its 
relation to them is, and it is possible that its opening is upon the base of the second 
instead of first maxilla. 
In the second Protozoea stage the two pigment-spots (p) on the carapace become 
extremely dendritic, and a pair of anal pigment-spots (Plate 3, fig. 34, pp) make 
their appearance on the telson on each side of the anus. 
At this stage the area, when the oesophageal muscles are attached to the carapace, 
is somewhat peculiarly marked by six little circles arranged in a pentagon, as shown, 
highly magnified, in fig. 35a. 
