ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 205 



by a loss of certain characters and a concomitant acquisition of new 

 features adapted to the change from free-swimming; to creeping life. 

 There is evidence that the entire creeping surface of Cceloplcma is derived 

 from a turning out of a large part of the inner pharyngeal surface of 

 ordinary Cydippids. It seems that the flatness of the body in this 

 aberrant form is largely due to this, and not merely to a reduction of the 

 vertical axis of the body. J. K. T. 



Ciliary Action in Pleurobrachia pileus. — James F. Gemmill 

 {Proc. Zool. Soc, 1918, 263-5, 2 figs.). In the internal cavities of this 

 Ctenophore there is very orderly "circulation" maintained by ciliary 

 action, and detected by the motion of particles suspended in the contained 

 fluid — e.g. small oil globules, alimentary particles and debris. There are 

 aboralward and oralward currents in the stomodteum, and there is a 

 more complex circulation in the canal system. J. A. T. 



Gastrodes parasiticum Korotneff. — Taku Komai {Annot. ZooL 

 Japon.^ 1920, 9, 585-90). An account of this imperfectly l^nown and 

 remarkable parasitic Coelenterate, found embedded in the test of Salpa. 

 Korotneff, the discoverer of the animal, referred it at first to the 



^.e 



Dorsal view of an early stage of Gastrodes parasiticum Korotneff. x 90> 

 ce., oesophagus; w.c, meridional canal ; t.h., tentacle basis. 



XarcomedusEe and afterwards to the Actiniae. Heider regarded it as a 

 degenerate Ctenophore, and Ctenophore it is. The colourless disc-like 

 body is more or less convex on the dorsal side, and measures • 5-3 mm. 

 in diameter. The gastrovascular system is represented by a connected 

 pair of cavities, each laterally divided into four peripheral pouches ; the 

 oesophagus is not laterally compressed ; the tentacle apparatus is indi- 

 cated by mere thickenings of the epidermis, and the aboral sense-orgau 

 by a shallow depression containing as yet no otolithic mass. From 

 such simple stages there is a gradation to forms with eight rows of comb- 

 plates, an aboral sense-organ, and a tentacle apparatus. It is likely that. 



