Royal Physical Society. 369 



III. (1.) On Reproduction by Ova from the Medusoid of Campanularia 

 Johnstoni. (2.) On Ephelota coronata, a new Protozoan animalcule. 

 By T. Strethill Wright, M.D. 



1. Campanularia Johnstoni. 



Campanularia Johnstoni occurs commonly at low-water, 

 on the shores of the Firth of Forth, and is doubtless very 

 familiar to many of the members of this Society. 



At all seasons of the year it produces campanulate medu- 

 soids (Plate XIX., fig. 3), each having four tentacles capable 

 of great extension, four intermediate rudimentary tentacles 

 and eight auditory organs, consisting of sacs, each containing 

 a single spherical crystal of carbonate of lime, and situated 

 one on each side of each of the rudimentary tentacles. 



The medusoids are produced within coarsely- annul ated 

 capsules, developed generally from the creeping fibre which 

 unites the polyp-stems ; but sometimes also from the polyp-stem 

 itself, in which case the stem is generally branched, and the 

 capsule axillary. The capsule is traversed by a fleshy axis, 

 dilated at its summit From this axis, which may be con- 

 sidered as a reproductive polyp, homologous with the reproduc- 

 tive polyp of Hydractinia, the medusae pullulate, inclosed within 

 sacs formed by a layer of ectoderm derived from the fleshy axis 

 of the capsule. The tissues of the medusoid are developed from, 

 and continuous with, both the layers (endoderm and ectoderm) 

 of the axis, and are at first a mere diverticulum thereof, as I 

 have described to the Society in the case of the medusoid of 

 Eudendrium. 



The medusoid of C. Johnstoni was described by the Rev. T. 

 Hincks in August 1852, and again by Mr Gosse in 1853, 

 neither of which gentlemen detected in it any ovaries, though 

 Mr Gosse has figured enlargements on the lateral canals (fig. 

 3, a), where those organs exist. 



In spring last, I obtained a large number of these medu- 

 soids from a specimen of Campanularia Johnstoni in my 

 possession ; and on examining some of them directly after their 

 escape from the capsule, I was surprised to find that the en- 

 largements figured by Gosse contained ova (fig. 4), with the 



