218 Proceedings of the Royal Physical Society. 



twenty times as long as the animal, and clothed at its upper 

 part by about forty scattered tentacles, which twine about 

 in most violent motion. The animal seems to be constantly 

 searching the water around for prey, and occasionally to 

 press the tentacles firmly against the body of the proboscis, 

 as if to imbed some matter into the soft substance of the 

 latter — the usual mode of feeding amongst the Acinetiens, to 

 which class it belongs. It is impossible not to be struck 

 by the extreme similarity in outward form between this 

 animal and the Echinoderm Sipunculus Bernhardt. In both 

 animals occur the same shapeless body, the same entirely 

 retractile proboscis crowned with tentacles, and the same 

 peculiar motions in seeking for prey. But with the form, 

 the similarity ends, for the Echinoderm possesses a highly 

 organised structure, while in the transparent Protozoon no 

 structure at all has been detected. 



(2.) On Hermaphrodite Pieproduction in Chrysaora hyos- 

 cella. (Plate IX). — Professor Allen Thomson, in his " Trea- 

 tise on the Ovum,"* states that " the Discophorse (Medusas) 

 are of distinct sexes." I have found this to be the case in 

 all the Steganophthalmata and Gymnophthalmata which I 

 have examined, with the exception of the subject of this 

 notice. 



Large individuals of C. hyoscella are hermaphrodite ; but 

 smaller ones are found which are unisexual, the male or 

 female element being suppressed, as in some dioecious plants. 



The best method of examining the structure of the repro- 

 ductive apparatus of this animal is to place the Medusa, in 

 its natural position, in a large basin of sea-water. The um- 

 brella, all but its margin, is then to be cut away. The cavity 

 of the stomach is thus laid open, and we have a good view 

 of the interior aspect of the sub-umbrella. We find that 

 each lip of the mouth divides, at its insertion, into three 

 pillars. The central pillar projects as a large rounded bulb 

 into the stomach, while the lateral ones diverge, pass out- 

 wards towards the margin, and afterwards converge and 

 unite together, so as to form, with the bulb of the central 

 pillar, the thickened opening or framework of the ovarian 



* Cyclopaedia of Anatomy and Physiology, vol. v. p. 129, " Acalephse." 



