80 A. C. QUDEMANS. 
PLATE III. 
Fre. 55.—The median vessel leaves the proboscidian sheath in the cesopha- 
geal region : drawn from a preparation of Valencinia longirostris, Quatr. 
Fic. 56.—Foremost open communication of the nephridial system with the 
blood-vessel in Carinoma Armandi (McInt.), Oud. The true nephridial 
canal arises from the tissue of the wall of the vessel, which in the neighbour- 
hood of the opening is of totally different structure from the rest. 
Fie, 57.—Second open communication of the nephridial system with the 
blood-vessel in Carinoma Armandi (McInt.), Oud. 
Fies. 58, 59, 60, and 61.—A series of four transverse sections through 
Carinoma Armandi (MclInt.), Oud., to justify the sketch No. 31. ; 
Fic. 62.—Transverse section through one of the lateral vessels of Lan gia 
formosa, Hubr. 
Fic. 63.—Transverse section through one of the lateral vessels of Langia 
formosa, Hubr., with a longitudinally-cut transverse vessel. 
Fic. 64.—A transverse vessel seen lengthways in a transverse section of 
Langia formosa, Hubr. 
Fic. 65.—Transverse section through a transverse vessel of Cerebratulus 
marginatus, Ren. 
Fic. 66.—Transverse section through one of the lateral vessels of Cere- 
bratulus hepaticus, Hubr. 
Fic. 67.—Longitudinal section (vertical) through the precerebral region 
(before the opening of the proboscidian sheath) of Valencinia longiros- 
tris, Quatr. An upper and a lower lacuna are visible in this section. Com- 
pare Fig. 53. 
Fic. 68.—Transverse section through the foremost part of the median 
vessel, lying in the proboscidian sheath of Polia curta, Hubr. 
Fre. 69.—Transverse section through the median vessel, lying in the pro- 
boscidian sheath of Drepanophorus rubrostriatus, Hubr. 
Fic. 70.—A small vessel in the gelatinous tissue of Amphiporus hasta- 
tus, McInt., transversely cut. 
Fic. 71.—Ditto, as seen lying in a transverse section. 
Fic. 72.—The supra-proboscidian-sheath-vessel from the right side in 
Carinoma Armandi (Mclat.), Oud., transversely divided into two. 
Fic. 73.—The same, normal. 
Fic. 74.—The lateral vessel of Carinoma Armandi (McInt.), Oud. Partly 
obliquely severed. An inner epithelium-layer, a hyaline basal-layer, a layer of 
protoplasmic cells passing into fibres which run round the vessel, and a 
layer of the same kind of cells which run along the vessel are distinctly 
visible. 
Fic. 75.—The lateral vessel of Carinoma Armandi (McInt.), Oud., 
transverse section. 
