Explanation of the plates. 

 Plate I. 



Fig. 1. Genital pinnule of Antedou prolixa (d"). ^'/i. 



- 2. Distal end of a pinnule of Antedon prolixa. ^Vi. 



- 3. Joint of a pinnule, ^vith the covering-plates, sacculi and tentacles 



of Antedon prolixa. *^/i. 



- 4. Genital pinnule of Antedon Eschrichti; dried, ^/i. 



- 5. Distal end of a pinnule of Antedon Eschrichti. ^Vi- 



- 6. Joint of a pinnule of Antedon Eschrichti, sho^ving the covering- 



plates, sacculi and tentacles, ^^/i. 



Plate П. 



Fig, 1. Valve of forcipiform pedicellaria oi Asterias panopla; seen from the 

 inner surface. '^°/i. 



- 2. The same of Asterias Millleri. ^^^/i. 



- 3. The same of Asterias Linckii. ^°/i. 



- 4. Sphaeridia (secondary mouthspine) of Pteraster militaris. ^°li. 



- 5. The outer end of the same. ■'°/i. 



- 6. Portion of the abactinal skeleton of Solaster ptapposus, var. squamata 



Döderl. 8/i. 



- 7. Portion of the abactinal skeleton of СпЬгеИй Srtw^rtmioZewia, Var. ^Vi. 



- 8. Portion of the abactinal skeleton of a specimen of Cribrella sang- 



uinolenta from the Cattegat, intermediate between the Var. and 

 the typical form. i*/i. 



- 9. Portion of the abactinal skeleton of Cribrella sanguinolenta, typical 



form. >Vi. 



- 10. Portion of the disc-skin of Ophioscolex glacialis, showing the trans- 



formed scales. ^Vi. 



All the figures are drawn with Abbe's Camera; the micro- 

 scope used, for which I am indebted to the Carlsberg Fond, 

 is a Zeiss's-instrument. 



