EEPORT ON THE ANNELIDA. 
415 
tube is present in the collection, and nothing is known of its habits. The curved 
anterior margin of the region shows a double ridge with a groove between. The outer 
ridge has the dark brown belt studded with the white papillae, formerly alluded to, along 
its external aspect, while internally, a continuous one of the same colour extends from 
the ventral to the dorsal margin. Upon the ridge are the outer paleae, which form a 
single row. They possess a stout shaft (PI. XXVa. fig. 16 ) for insertion into the tissues, 
its lower region being marked by close transverse lines, then by similar but slightly 
wavy lines, further up, below the pectinations, by a wider series of lines still more 
undulated, which present lateral ridge-like projections, the part immediately adjoin- 
ing the pectinations, indeed, somewhat resembling the minute structure of wool. This 
region is also constricted. The lateral ridge-like processes gradually increase in distinct- 
ness from below upward, and soon assume the appearance of curved pectinations, which 
become longer toward the tip, the latter very rarely being perfect, probably from the 
brittle nature of the tissue. It is difficult to get a complete view of the pectinations on 
both sides, probably because the palese are twisted. The undulating transverse lines 
pass upward a little after the pectinations begin, then become indistinct and disappear. 
On the outer border of the ridge are the whitish papillse, from seven to nine in number. 
The largest and longest is the last at the ventral edge, and it points inward from the 
prominence at the commencement of the inner palese. The last dorsal is small, and is 
situated just opposite the base of the great chitinous hook on each side. The inner 
ridge is less supplied with pigment than the outer, in one exam23le being perfectly pale, 
while in another a pale brownish belt occurs externally, and an intensely brownish 
portion both externally and internally at each end, where it joins the outer row. The 
inner palese spring from the top of the ridge, increasing in length from above downward 
toward the ventral series. These processes are hollow and somewdiat triangular in 
transverse section, diminishing superiorly and interiorly. The tip (PI. XX Va. fig. 17) is 
slightly curved and moderately pointed, while the central cavity nearly reaches the 
extremity. A series of transverse bars occurs both superiorly and inferiorly, and 
are probably due to septa which strengthen the somewhat brittle organs. While the 
outer row has a tendency to slope externally, these slant decidedly forw^ard and inw^ard. 
They are very brittle, rarely more than the tip remaining entire after mounting, as in 
the figure. 
Inferiorly the cephalic fissure is very extensive, each limb presenting a linear series of 
transverse ridges, from ten to twelve in number. From these and the rest of the opposing 
surfaces the dense masses of filiform branchiae arise. 
The mouth opens just behind the ventral fork as a prominent orifice, provided 
anteriorly with two large labial palpi, and laterally with a lanceolate cirrus. The external 
fold of the mouth forms a thick crenate margin, while a pair of thinner and somewhat 
frilled inner lips occurs between them. Deep brown pigment exists round the mouth, 
