PLATE XV. 



Fig. 1. Cerebral ulii-i- lonf/ijissus, n. sp. Transverse section througli the proboscidian sheath, a, the 

 inner longitudinal muscular laj^er of the body wall; pr.sn, the proboscidian sheath nerve; 

 Pr.S, the lumen of the proboscidian sheath; e, its inner epithelial Uning; b, the homo- 

 geneous basement membrane of this epithelium, traversed by radial fibres and separatin.; 

 the aforesaid epithelium from the muscular layers (an inner longitudmal, and an outer 

 circular) of the proboscidian sheath ; Gi, the gelatinous tissue between the proboscidian 

 sheath, the intestine and the body wall ; dv, the dorsal blood-vessel. 



Fig. 2. Cerebrafuhis marroren, n. sp. Transverse section of the proboscis, b, the ensheathing mem- 

 brane ; a and y', the two layers of longitudinal, /3', the layer of circular muscular fibres, the 

 latter connected crossways at two diametrically opposite points with the membrane b ; 7i.pl, the 

 nerve-plexus between /3' and y'; £, the very high inner epithelium with smaller (c) and 

 larger (C) batteries of nematocysts. 



Fig. 3. Cerebraiulus macroren, n. sp. Transverse section of the proboscis much further backwards ; 

 the proboscis is thinner, the muscular fibres (a) only longitudinal, the epithelium (^E) 

 flattened, the nervous plexus replaced by two lougitudinal nerve-stems N. 



Fig. 4. Cerebraiulus angusticepis, n. sp. Head, a, from below ; b, side view. 



Fig. 5. Cerebraiulus parkeri, n. sp. Head, a, side view ; b, from below. x 1 i. 



Fig. 6. Cerebraiulus sp. inc. Two fragments from Japan. x 2. a, dorsal view ; //, ventral view. 



Fig. 7. Cerebraiulus sp. inc. Transverse section of one of the fragments of fig. 6. /, the integu- 

 ment ; a, /?, and y, the much reduced muscular layers ; N, the lateral nerve-stems ; Int, the 

 intestinal canal and cajca, suspended in the gelatinous ground tissue Ot ; Gi', the same tissue 

 expanded between the very sparse external fibres of the muscular layer y ; PrS, the probo.s- 

 cidian sheath ; bv, the blood-vessels. 



Fig. 8. Cerebraiulus sp. inc. Lateral view of the head of another specimen from Japan (Kobe). 



Fig. 9. Cerebraiulus loru/ijissus, n. sp. Longitudinal section of the tail end. /, the integument ; 

 l7ii, the intestinal epithelium ; a, /3, y, the muscular layers ; 712^1, the nerve plexus. This figure 

 is meant to show the general aspect of the muscular layer a, more highly magnified in fig. 10. 



Fig. 10. Cerebraiulus lo7igifissus, n. sp. The muscle-fibres of the layer a are seen tojDresent a more con- 

 siderable diameter in successive vertical planes, forming rings round the intestine and alternating 

 with others in which this increase in diameter is not visible. Nuclei are also more numerous 

 in the former portions than in the latter ; Ep, the intestinal epithelium ; Gt, the gelatinous 

 tissue between this and the body musculature, with bundles of radial fibres. 



Fig. 11. Am2>liiporus 7noseleyi, n. sp. Transverse .section of the lateral region with glandular cavities 

 (gl), arranged along the lateral line between the dorsal and ventral musculature a, piercing 

 the circular muscular layer fi at c, and suspended by the gelatinous tissue gt. I, integu- 

 ment ; B, basement membrane. 



Fig. 12. A7uphiporus 7noseleiji, n. sp. One of the glandiilar caeca, more considerably magnified, with 

 granular epithelium and flattened nuclei exteriorly, the latter belonging to the surrounding 

 gelatinous tissue. 



Fig. 13. Drepa7iopihorus lankesteri, n. sp. A section of similar glandiilar caeca in the dorso- median region 

 of the head. 



Fig. 14. Amphiporus 7narioni, n. sp. A very unripe generative caecum, not yet ojjening to the exterior. 

 fi. Circular, a, longitudinal muscular layer. The caecum reaches down into the gelatinous 

 tissue, gt. 



Fig. 15. Amphiporus marioni, n. sp. Ova in different stages of development. 



Fig. 16. Cerebraiulus jjarkeri, n. s^i. An ovum. 



Fig. 17. Dreiianophorus .ierraticollis, Hubr. An ovum. 



Fig. 18. Cerebraiulus sp. inc. A batch of ova from a ripe generative cjecum of a specimen from Station 



321. The ova are surrounded by a hyaline membrane (which has erroneously been dotted 



by the lithographer) and pressed into polygonal shapes. 

 Fig. 19. Cerebraiulus marrore7i, n. sp. Part of a transverse section, in outline. Prs, The cavity of the 



proboscidian sheath ; I, integument ; y, /8, the muscular layers ; N, the longitudinal nerve-slem ; 



ge.c, the generative caecum ; o, its exterior opening. The duct to this opening, where it 



pierces the layer y, is considerably extended in bulk. 

 Fig. 20. Ampjhiporiis moseleyi, n. sp. A longitudinal section through the greater part of the compressed 



oesophagus Oe, and subjacent intestinal caeca (co). 



