PLATE X. 



Fig. 1. AmpJiiporus marioni, n. sp. Part of a transverse section through the oesophageal region, indi- 

 cating the relative importance of the musculature with respect to the integument and the 

 gelatinous tissue. Prs, proboscidian sheath in contracted state, the outline only partly 

 worked up to show the interlacement of muscular fibres, the basement layer and the internal 

 epithelium ; dv, dorsal blood-vessel surrounded by gelatinous tissue, as is the proboscidian 

 sheath, and Oe, the resophagus with its cellular epithelium. Outside of this there is a layer 

 of darker fusiform bodies, which are most probably unicellular parasitic organisms. Gt, the 

 gelatinous tissue ; a, the longitudinal, B, the circular muscular coat ; at ne, a bundle of nerve- 

 fibres spreads between a and B after having traversed the musculature between two of the 

 larger bundles of a ; B, thick basement' membrane with only a few nuclei ; J, integument ; 

 LX, longitudinal nerve ; Nep, nephridial tubules ; Nep.d, part of the communicating duct 

 of the nephridia with the exterior ; inc, peculiar crystalloid inclosures of a greenish colour, 

 irregularly distributed in the gelatinous tissue. 



Fig. 2. Drepanophorus lankesteri, n. sp. Part of a section through the tail end. J, the integument, with 

 an outer layer of sense-cells and supporting cells ; granular glands leading to the exterior, a 

 layer of nuclei and one of deep lying cells with fainter nuclei ; B, basement membrane with 

 imbedded nuclei ; a, the longitudinal, B, the circular muscular layer ; Gt, the gelatinous 

 tissue with nuclei and cells inclosed, certain of these being on their way of transformation 

 into fibres ; LN, longitudinal nerve-stem. 



Fig. 3. AmpJiiporus moseleyi, n. sp. Horizontal section through the tip of the snout. Pr, proboscis 

 and its musculature passing into and being the direct continuation of a, the longitudinal 

 muscular layer ; Prs, the proboscidian sheath; Sp.Pr, muscular arrangement in the wall of 

 the rhynchodseum constituting a sphincter; Rh, external opening of the rhynchodseum, which 

 is internally clothed b}' a layer of cells very gradually passing into the proboscidian epithelium, 

 and externally into ./, the integument ; B, basement membrane ; B, circular muscular layer, 

 obliquely cut ; Gt, gelatinous tissue ; Br, Br', left and right brain-lobes ; E, eyes ; gls, lateral 

 glands, continued along both sides of the animal (c/ PI. XV. figs. 11, 12). 



Fig. 4. Drepanophorus lankesteri, n. sp. Proboscidian sheath with diverticula (div.Prs). Prs.ep, epi- 

 thelium of the sheath, separated by folded basement tissue from the muscular wall. 



Fig. 5. Drepanophorus serraticollis, Hubr. Proboscidian sheath with thicker muscular walls and thinner 

 walled diverticula (div. Pr*.). 



Fig. 6. Eupolia giardii, n. sp. The boundary line between integument and body musculature. Jdvl, 

 deeper layer of vacuolated cells of the integument ; B, reduced and folded primary basement 

 membrane ; y.vl, outer longitudinal muscular layer with large vacuolated cells and rare muscle 

 fibres. The vacuolated cells have larger nuclei than those of the integument (cf. PL VII. 

 fig. 5). 



Fig. 7. Cerebratulies sp. iuc. (medullatus ?). Transverse section of medio-dorsal region. J, integument; 

 b, secondary basement membrane ; y, outer, a, inner longitudinal, B, circular muscular layer ; 

 Prs.ep, epithelium of the proboscidian sheath ; PrsN, longitudinal nerve of proboscidian 

 sheath ; ne, nervous layer with median medullary thickening. 



Figs. 8, 9. Cerebratulus macroren, n. sp. The proboscidian sheath wall and intestinal epithelium wholly 

 (fig. 9) and half (fig. 8) distended by the proboscis, dv, dorsal blood-vessel (in fig. 8 still 

 within the proboscidian sheath cavity); Prs.ep, the epithelium of the proboscidian sheath, 

 supported by a homogeneous membrane, b, and surrounded by muscular layers m.Prs. Oe.ep, 

 epithelium of the oesophagus. 



