852 A TURRIS OVIPOSITING. 



of the peduncle to the margin. This course is not a 

 straight but a curved one. When therefore these 

 bands are simultaneously and forcibly contracted in 

 length, they are drawn from a curved into a straight 

 line, and the cavity which was bell-shaped becomes 

 more conical, and its capacity is considerably dimin- 

 ished ; a portion of the water which it before held is 

 therefore driven out at the mouth, and by its reaction 

 forces the animal forward with a jerk in the opposite 

 direction. I think, however, that the action of the 

 radiating bands of muscle is aided by circular bands 

 lining the sub-umbrella, as well as by the marginal 

 one ; for when a Turris in strong contractions is at- 

 tentively watched in an upright position, there are 

 seen indrawings of the sides from the perpendicular at 

 every contraction, that the shortening of the radiating 

 bands is not sufficient to account for. 



Fig. 8 represents a Turris in the state of oviposit- 

 ing; the peduncle enormously swollen and become 

 globose, with its lower part showing the four orange 

 ovaries, distended with purple gemmules. It lies on 

 its side on the bottom, the four lips protruded at one 

 extremity, and around the other the diminished and 

 reverted umbrella gathered in small vesicular puckers. 

 In this condition one would not recognise it as a 

 Medusa, if not familiar with it."^" The oval purple 



* Of the scores of this species that I have kept, this was the common, 

 and therefore, I presume, the natural, termination of life, Mrs. Davis, 

 in the interesting note of one kept hy her, communicated to the Ann. 

 N. H., vol. vii, alludes to it. " At the end of a fortnight one of my pets 

 turned itself inside outwards, and remained in this state for some time, 

 when it died, and left only a few floculent particles at the bottom of the 

 vessel." I do not doubt that if the sediment had been carefully ex- 

 amined with a microscope, the intelligent observer would have dis- 

 covered among it many of the crimson oval gemmules. 



