564 DIl. J. F. GEMMILL ON THE 



References. 



1. Gemmill, James F.— The Development of tlie Starfish Solaster 



endeca (Forbes). London, Trans. Zool. Soc. vol. xx. pt. i. 

 pis. i.-v., pp. 1-71. 1912. 



2. Do, do. The Development and certain points in the 



Adult Structure ot" the Starfish Asterias ruhens L. Phil. 

 Trans. Roy. Soc, Ser. B, vol. ccv. pp. 213-294. 1914. 



3. Do. do. The Larva of the Starfish Porania pidvillus 



(0. F. M.). London, Q. J. M. S. vol. Ixi. pt. i. pp. 27-50. 

 1915. 



4. Do. do. Double Hydrocoele in the Development and 



Metamorphosis of Asterias ruhens L. London, Q. J. M. S. 

 vol. Ixi. pt. 1, pp. 51-80. 1915. 

 6. Goto, S. — Some Points in the Metamorphosis of Asterina 

 gibhosa. Tokyo, Journ. Coll. Sci. vol. xii. pt. 3, pp. 227- 

 242. 



6. LuDwia, H. — Entwickelungsgeschichte der Asterina gibhosa. 



Leipzig, Zeitschr. Wiss. Zool. vol. xxxvii. pp. 1-89. 

 1882. 



7. MacBride, E. W. — The Development of Asterina gibhosa. 



London, Q. J. M. S. vol. xxxviii. pp. 339-411. 1896. 



8. Do. do. Text-Book of Embryology. Vol. I. Inverte- 



brates. London, Macmillan & Co. 1914. 



9. Masterman, a. T. — The Early Development of Crihrella 



oculata (Forbes), with Remarks on Echinoderm Develop- 

 ment. Edinburgh, Trans. Roy. Soc. vol. xl. pp. 373-417. 

 1902. 



10. Sars, M. — XJeber die Entwickelung der Seesterne. Arch. f. 



Naturgesch. 1844, pp. 169-178. 



11. Sladen, W. p. ' Challenger ' Reports : Zoology, vol. xxx. 



1889. 



12. Spencer, W, K. Monograph of the British Pala?ozoic 



Asterozoa. Part 1. Pal£eontographical Society, 1913, 

 pp. 1-56. 



EXPLANATION OF THE PLATES. 

 Plaxe I. 



Asterias glacialis. 



Fig. 1. Larva, 8 days old, showing on left side a well-marked posterior body 

 becoming separated off' from the wall of the stomach. 



Fig. 2. Larva from same brood, 12^ days old, showing the posterior enterocoelic 

 body now separated off from the stomach, possessing a lumen of its own, 

 and increasing in size. The right and left enterocreles are growing back- 

 wards along the sides of the stomach. This larva, like many others m 

 A. (jlacialis, has a right as well as a left hydropore. 



Fig. 3. Larva from same brood, 15 days old, showing the posterior enteroccelic body 

 now united with the main enterocffile on the left side. This larva also lias 

 two hydropores, but the right one is becoming reduced. In older larvaj 

 the coelom extends still further backwards on the sides of the stomach as 

 in Asterias ruhens (2), but it is then no longer possible to tell on the left 

 side what portion is derived from the posterior enteroca'lic body. 



