Plate V. 



Figures i — 2. Phial idiion islandicum nov. spec. 



Figure i. Part of the bell-margin, showing marginal vesicles alternating with the tentacles. — Iceland, 

 "Thor" Stat. 176(04). — x 20. 



— 2. Longitudinal section through a tentacular bulb, perpendicularly to the circular vessel. — 



Iceland, "Thor" stat. 266 (04). — x 50. 



— 3. PInalidiiim lieniisplKertciiiii (Gronovius). — Longitudinal section through a tentacular bulb, 



perpendicularly to the circular vessel. — Myri Bugt, Iceland. — x 50. 



Figures 4 — 10. Thna bairdii (Johnston). 



— 4. Dorsall wall of the stomach, showing the four deeji grooves and the entrances to the four 



radial canals; the two entrances to the left are closed, the two others are open, showing 

 the transversal folds in the proximal part of the radial canals. The lateral walls of the 

 stomach have Ijeen removed. — From a Danish specimen. — x 8. 

 — 5. Lateral view of the manubrium and the lower end of the stomachal peduncle; showing the 

 four large, folded lips and the triangular pouches between the dorsal wall of the stomach 

 and the peduncle. The cross-shaped figure, along the arms of which the stomacli is attached 

 to the peduncle, is discerned through the jelly of the latter. In this specimen the "cross- 

 arms" do not meet exactly in the centre. — From a Danisli specimen. — x 8. 



— 6. Part of the bell-margin, seen from the abaxial side, with two tentacles (observe the abaxial 



spur-like projection at the base of the bulbs) and a number of marginal warts and marginal 

 vesicles. — From a Danish specimen. — x 5. 



— 7. Lateral view of a tentacular bulb. The margin of the umbrella, the circular vessel, and the 



velum are seen in section. The basal spur on the tentacular bull? is distinctly visible. Above 

 the tentacle is seen the rounded gelatinous protuberance of the exumbrella. — x 5. 



— 8. Section through the bell-margin and a tentacular bulb; showing the entodermal, basal spur, 



covered by the epithelium of the exumbrella. — x 12. 

 9. Section through the bell-margin. The section has passed through the middle of a marginal 

 wart with a marginal vesicle situated on the adaxial side close to the velum. — x 65. 



— 10. Transverse section through a radial canal (the part on the stomachal peduncle) with male 



gonads; showing the mode of attachment to the subumt)rella, mentioned in the text, p. 103. 

 — X65. 



