MIOEOHYDRA RYDBET. 633 



Fig. 12. — Medusa of Limnocnida tanganyicse. After Moore, 'The 

 Tanganyika Problem,' 1903, p. 299. 



PLATE 36. 



Pigs. 13 and 14. — Medusa of Microhydra ryderi, lateral and polar 

 aspects. Drawings made by Dr. J. P. Moore, x 116. 



Figs. 15 and 16. — Medusoid bud developing upon a liydroid colony of 

 Microhydra ryderi. Two stages, drawn by the author, during the after- 

 noon and evening of the same day. 



Figs. 17 — 20. — Drawings of Microhydra ryderi, made by Dr. J. A. 

 Ryder (see text, pp. 626-7). 



Figs. 21 — 25. — Drawings of Microhydra ryderi, by the author (see 

 text, p. 627). 



Fig. 26. — Section across a mature hydroid of Microhydra ryderi. 

 Drawn bv Dr. J. P. Moore, x 480. 



Note on the Foregoing by E. Ray Lankester. 



Mr. Potts lias been so very kind as to send to me, at my 

 request, a specimen of the minute medusa liberated by 

 Microhydra and preserved in formalin. It is one of two 

 which remained in his possession. Whilst further study of 

 Microhydra and its medusa is urgently called for, it is 

 clear that further research is needed in order to settle the 

 doubt entertained by Mr. Potts as to the actual genetic con- 

 nection of Bourne's hydroid with the medusa L im no- 

 cod ium. It is within the bounds of possibility that that 

 hydroid is a native European hydroid, similar to Microhydra, 

 and not connected with the Limnocodium life -cycle. 



