MONILIGASTER GRANDIS, A. G. B. 379 
PLATE 25, 
Fic. 27.—M. grandis. A dissection of the anterior region. The seg- 
ments as defined by the intersegmental grooves are marked vi to xiv. Certain 
of the segments as defined by the septa are marked rx, x, xz, x1. The cut 
edges of certain septa are marked 9/10, 10/11, 11/12. 0. s., 7.s. Outer and 
inner seta lines. 
Nervous System.—The cerebral ganglion, cesophageal commissures, 
the ventral nerve-cord, and some of the nerves are shown. In the cerebral 
ganglion the bilobed ganglionic mass is shown surrounded by the sheath. 
N. Pro. Prostomial nerves. . N. 1, N. 11, &c. Nerves belonging to the 
Segments 1, 11, &c. The five pairs of nerves to the cesophageal wall are 
shown. A small portion of the thick septum 7/8 is left undissected away to 
show the anterior nerve of Segment vir passing into its substance. The 
nerves in most segments are shown only up to the inner seta line where they 
pass into the muscular layers, but in Segment 1x and a portion of Segment x 
these are dissected away to show the distribution of the nerves. 2. 1, x. 2, 
n.3. The three nerves of the segment. ~z. sept. Branches supplying the 
septum. .v. Nerve to the viscera of the segment. 2. 2. Nerve joining 
a. 3 with the septal nerve of the next following segment. Some portion of 
the septa 9/10, 10/11, 11/12 having been left, the nerve-cord disappears for a 
time in Segment x to reappear in Segment x1 (as defined by the septa, the 
great development of the lumen of Segment x1 throws this region back to 
Segment xiv, as defined by the intersegmental groove). The curved arrow 
shows where the nerve-cord passes into Segment x11, and then under Seg- 
ment x1. As a matter of fact, if Segment x1 was filled with ova, &c., not 
only the nerve-cord but the ventral vessel and the cesophagus would not be 
seen in this region. 
Nephridia.—The position of the external apertures of the nephridia of 
Segments 111 to x11 are shown on the right-hand side ; of Segments 1x to x11 
on the left-hand side, and marked by a small circle with the numbers 38, 4, 5, 
&e., by the side. In the case of the nephridia of Segments x—x11I a small 
portion of the excretory duct is drawn to show how the ducts of the nephridia 
of Segments x and x1 carry the septum forward to its true position. On the 
left-hand side the marks x. 3, 2. 4, 7. 5, &c., enclosed by a line, indicate the 
nephridia supplied by the blood-vessels which touch the line in question. 
Vascular System.—The exact arrangement of the vessels must be fol- 
lowed from the text. Note:—The ventral vessel, V. V.; the branches, 
Br. V. T., of the ventro-tegumentary vessels of Segments 1 and 11; the 
ventro-tegumentary vessels, V. T., of Segments 111, Iv, and v, the latter 
supplying, besides the body-wall, &c., the salivary glands (vessels marked 
Sal.) and the nephridia of those segments; the ventro-intestinal vessels 
V. 1, the most anterior one in Segment v1; the “ventro”-tegumentary 
