18 



DR. J. P. GEMMILL ON THE 



2. Gemmill, J. F. — The Development of the Starfish Solaster 



endeca Forbes. Trans. Zool. Soc. London, vol. xx. pp. 1-71, 

 pis. i.-v. (1912). 



3. Gemmill, J. F. — The Larva of the Starfish Porania pulvillus 



(0. F. M.). Report Brifc. Assoc. 1913, Section D, p. 511. 



4. Gemmill, J. F. — The Development and Certain Points in the 



Adult Structure of the Starfish Asterias rubens L. Phil. 

 Trans. Roy. Soc. London, 1914, B, pp. 213-294. 



5. MacBride, E. W. — The Development of Asterina gibbosa. 



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



6. Semon, R. — Die Entwickelung der Synapta digitata und die 



Stammesgeschichte der Echinodermen. Jen. Zeitschr. Natw. 

 vol. xxii. pp. 175-302 (1885). 



7. Stephenson, J. — On Intestinal Respiration in Annelids. 



Trans. Roy. Soc. Edinb. vol. xlix. pt. 3 (no. 14), pp. 735-829. 



EXPLANATION OF THE PLATES. 



Lettering and Signs. 



Amb.Gr. Ambulacral groove. 



Amb.Gr.' In fig. 1, portion of an am- 

 bulacral groove covered in 

 by interlocking of spines 

 (see p. 13). 



Amp Ampulla of sucker-foot. 



Coel Perivisceral coelomic cavit}'. 



G Gill. 



G-.' Three inframarginal gills 



(abnormal) in the Porania 

 shown in fig. 1 (see p. 21). 



Gon Gonad. 



Gr Groove separating stomachal 



from pyloric-sac portions 

 of gastric cavity. 



% Current centripetal and at right angles to plane of drawing. 



+ Current centrifugal and at right angles to plane of drawing. 



>- Current as arrow points and in plane of drawing. 



f>— ■> Current as arrow points and in plane of drawing, but with centripetal 

 tendency. 



I — >j Current as arrow points and in plane of drawing, but with spiral 

 ~~ tendency. 



Plate I. 



Fig. 1. A specimen of Porania pulvillus from the oral aspect, with arrows indi- 

 cating the direction of the ciliary currents. See description on p. 3 

 and, in connection with feeding, p. 10. This specimen showed three 

 inframarginal gills (G.'), and is therefore so far an exception to the rule 

 that in phanerozonate Starfishes the gills should be confined to the supra- 

 marginal surface (see p. 21). 

 [2. Astropecten irregularis, with arrows indicating the direction of the sub- 

 paxillary ciliary currents on the aboral aspect, and also of the currents in 

 the marginal, interradial, and ambulacral grooves. See description on 

 pp. 3, 14. 



