ON ARHYNCHUS HEMIGNATHI. 27 
DESCRIPTION OF PLATE 12, 
Illustrating Mr. A. E. Shipley’s paper on “ Arhynchus 
hemignathi, a new genus of Acanthocephala.” 
In some cases the names of the various structures are written on the figures, 
in others the following abbreviations have been adopted. czve. mus. The layer 
of circular muscles in the skin. gez.d. Genital duct. gez.p. The external 
opening of the duct. dace. The lacune in the skin. Jda/. lac. The large lateral 
lacune of the trunk. dem. The lemnisci. Zig. The ligament. dong. mus. The 
longitudinal muscles of the skin. mus. The muscles from which the ligament 
arises. uc. The amoeboid nuclei of the skin and the lemnisci. sperm. Coagu- 
lated masses of spermatozoa in the body-cavity of the female. 
Fies. 1, 0, and 111.—Three views of three different specimens of Arhyn- 
chushemignathi. Hach x 20. The division of the body into three regions 
is well marked. The details are shown in Fig. 1. Figs. 1 and 1 are rough 
sketches. 
Fig. 1v.—A transverse section through the head of a female, crowded with 
ova and egg-masses; the ligament is shown in section. x 40, 
Fig. v.—A transverse section through the same, just below the edge of the 
collar. In the centre is the neck, which fuses with the collar a few sections 
further back. The big circular canal of the collar is shown at dae. x 40. 
Fic. vi.—A transverse section through the trunk of the same. The upper- 
most lemniscus is cut in two places. The ovary is double, and shows egg- 
masses as well as eggs; some coagulated masses of spermatozoa are lying in 
the body-cavity. x 40. 
Fic. vit.—A surface view of the external opening of the genital duct. 
x 40. 
Fic. vill.—Some developing ova, highly magnified. 
Vie. 1x.—A transverse section through the trunk near the genital pore, 
taken from the same series as figs. Iv, V, aud vi. It shows part of the funnel- 
shaped internal opening of the genital duct, gex. d. x 40. 
Fic. x.—A transverse section from another specimen taken behind the 
opening of the genital duct. This shows the arrangement of the lacune and 
their communications with the lateral lacune, /aé. lac. 
Fic. x1.—A longitudinal section through the central part of the skin of the 
head, showing the origin of the ligament and the ganglion cells of the brain, 
lying in a mass of ova and egg-masses. 
