422 



CTENOPHORA 



movements. Very little is known at present concerning many 

 details of the internal anatomy, but there is one point of con- 

 siderable theoretical interest — namely, the presence of definite 

 male genital ducts. 



Three of Dr. Willey's specimens were mottled with a green 

 pigment, whereas his fourth specimen and Korotneff's only speci- 

 men were mottled with a red pigment. It has yet to be deter- 

 mined whether the differences which have been observed in tlie 

 individual specimens are of specific value. 



Fam. 2. Coeloplanidae. — Coeloplana was originally discovered 

 by Kowalevsky in tlie Red Sea, but has recently been found by 

 Abbott ^ on the coast of Japan. 



The Japanese species are found principally on encrusting 

 Algae, Zostera, Ifelohesia, etc., which they resemble very closely 



in colour. The Red Sea species is, 



according to Kowalevsky, ciliated 

 all over, but the Japanese species 

 are ciliated only on tlie ventral 

 surface. As in Ctenoplana, the 

 body of Coeloplana is a flattened 

 ^^^ disc with a notch at each end of 



the tentacular axis, when creeping ; 

 ^j ^j-ii but Codojylana does not swim, nor 



" at any time does it assume a 



helmet -shape. The tentacles are 

 very long and of a chalky-white 

 colour. They can be retracted into 

 ^'^ lj> tentacle-sheaths. When the animal 



'Flu,. 18B.— Coeloplana mitsukurii, iioat- ig excited it thl'OWS Out the whole 

 iii2f at the surface of the sea with , , i • i i r i -i. £i 



the dorsal side downwards. T, T, tentacle m a cloud ol whitc fiia- 



the tentacles expanded. (After nicnts, "and to watch it at SUCh 



Alibott.) . - . , 1 . • 



a time, shooting out and retracting 

 the tentacles, moving along the side of the aquarium like a 

 battleship in action is truly a remarkable spectacle." " On the 

 dorsal side of the body there is a series of processes which are 

 called the dorsal tentacles. The statolith is very small, and 

 is not surrounded by sensory processes as it is in Ctcnoplana. 

 There are no ctenophoral plates. The colours of the Japanese 



^ Annot. Zooloij. Jupon. iv. ]it. iv. 1902, p. 100. 

 " A'obott, I.e. p. 106. 



