BROOKS AND RITTENHOUSB. On Turritopsis. 



PLATE 31. 

 The anatomy of Turritopsis. 



Letters of reference; a, cavity of radial canal; b, ectoderm of exumbrella; 

 c, jelly of umbrella; d, endodermal lamella; e, muscular layer of subumbrella; 

 /, ectoderm of subumbrella; </, endoderm on external surface of chymiferous 

 tube; h, endoderm on internal surface of chymiferous tube; n 1 , velar nerve- 

 ring; n 2, sensory nerve-ring; t, tentacle with ocellus; v, velum. 



Fig. G. Section through a radial canal close to its junction with the circular 

 canal. 



Fig. 7. Section through the circular canal and the base of a tentacle. 



Fig. 8. A drawing, made at Nassau, New Providence, in 1886, of a medusa, 

 which has recently been included in the genus, Modeeria. It is 

 here figured in order to show that it has nothing in common with 

 the genus Modeeria of Forbes, and is closely related to Turritopsis. 



Fig. 9. A cross section of the ascending region of the radial canal of Turritop- 

 sis, above its union with the horizontal region. 



