PLATE 8. 



Fig. 1-3. DOLABELLA AQASSIZI, Sp. nOV. 



Fig. 1. A group of seven epithelial cells from the mandibular sulcus region. Only the basal 

 portion a, of the euticular rodlets is shown; /, basal stratum of connective-tissue; b, b, two groups of 

 muscle-fibres, the freely branching ends of which penetrate the basement^membrane and ramify around 

 the basal ends of the epithelium-cells. In order to follow these branchings the focus has been changed 

 slightly in drawing. The longitudinal fibrillation of the cytoplasm of the epithelial cells appears to be 

 continuous beyond their distal ends into the cuticle itself. Celloidin section, Mallory's connective-tissue 

 stain. X 500. 



Fig. 2. Large subepitheUal gland-cell from near base of palatal flap. The epithelium is not rep- 

 resented, being stripped off from the basement-membrane, rf; the nucleus of the cell does not Ue in 

 the plane of the section. The cUlated proximal end of the cell shows clear reticular cytoplasm witli 

 deeply staining nodal points. The region b is filled with a homogeneous secretion, which exudes from the 

 tip of the cell at a, and passes up between the epithelial cells to their free surface. X 500. 



Fig. 3. Three epithehal cells from near the bottom of the mandibular sulcus; a, the short euticu- 

 lar rodlets; /, the basal stratum of compact connective-tissue, through which pass the richly branched 

 ends of two muscle-fibres, which terminate in it and between the basal ends of the epithehal cells e. 

 Fig. 1 and 3 show that a considerable amount of shrinkage has taken place in the epithehum, which 

 has rendered the termination of the muscle-fibres more evident. Hansen's iron hemato.xylin and 

 chromotrop 2B. X 500. 



Fig. 4. DoLABELLA HASSELTii (F6russac). 



Fig. 4. Cross-section of the pharyngeal bulb, taken in the region of the mandibles to show 

 their relations; o, outline of pharyngeal bulb; c, its lumen; m, mandibles, g, mandibular sulcus in which 

 the rodlets are produced. The plane of this section is slightly posterior to the dotted line indicating 

 the mandible m, in Fig. 5. X 12. 



Fig. 5-7. DoLABELLA AGASsizi, sp. nov. 



Fig. 5. Semidiagrammatic dorsal view of the interior of the pharyngeal bulb. The bulb has been 

 opened by a median dorsal longitudinal incision, and the sides have been reflected; m, the mandibles; 

 l.f, the palatal folds of the dorsal wall of the bulb, thickly set with the palatal spines; /, a transverse 

 ridge in the dorsal wall connecting the palatal folds; oe, the oesophageal end of the bulb. The radula 

 is seen in the centre of the organ, its anterior end buried in a deep curved groove. X 3. 



Fig. 6. A group of the numerous subepithelial gland cells imbedded in the connective-tissue of the 

 palatal flap, near the free margin. X 500. 



Fig. 7. Surface view of a portion of the mandible near its posterior border; o, yoimgest rodlets; 

 b, older ones. X 90. 



