Dr. T. S. Wright on Chrysaora hyoscella. 357 



Genus Homalenotus, Koch. 

 Homalenotus quadridentatus. 



I received a specimen of this species in 1857 from the Rev. 

 A. M. Norman, which had been captured at Brighton ; and the 

 Rev, 0. Pickard-Cambridge found several individuals among 

 moss and herbage, near Winchester, last year. All of these, as 

 well as the specimens which I myself obtained in Buckingham- 

 shire, were inhabitants of a chalky soil. 



XL. — On Hermaphrodite Reproduction in Chrysaora hyoscella. 

 By T. Strethill Wright, M.D. 

 [Plate XVIII.] 



Prop. Allan Thompson, in his Treatise on the Ovum *, states 

 that " the Discophorse (Medusse) 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 reproduc- 

 tive apparatus of this animal is to place the Medusa, in its na- 

 tural position, in a large basin of sea-water. The umbrella, all 

 but its margin, is then to be cut away. The cavity of the sto- 

 mach 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, ])ass outwards towards the margin, and after- 

 wards converge and unite together, so as to form, with the bulb 

 of the central pillar, the thickened opening or framework of the 

 ovarian pouch. This opening is closed by the ovarian mem- 

 brane, which consists of three layers — 1. the endoderm, or intes- 

 tinal layer ; 2. the gelatinous layer ; and 3. the ectoderm, or 

 dermal layer. The ovarian membrane appears as a flocculent 

 mass, from its being corrugated into numerous folds. By inject- 

 ing air beneath it, it becomes inflated, and the folds are opened 

 out. It then presents the appearance of a large transparent bag 

 traversed by flat convoluted bands. These bands are the ova- 

 ries, and contain, between their endoderm and gelatinous layer, 

 countless ova and planuloid larvae in various states of develop- 

 ment. 



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



