204 Dr. A. Korotneff on Polyparium ambulans. 



In a preliminary communication * I have already stated 

 that during my voyage to Malaysia I visited the channel 

 between the large island of Billiton and the smaller neigh- 

 bouring island of Mindanao lying to the west of the former. 

 This locality was particularly recommended to me by my 

 learned friend Dr. Sluiter, of Batavia, and with the greatest 

 justice. "While the neighbourhood of the islands to the east- 

 ward, between Billiton and the neighbouring islands (Pulu 

 Soukun and Pulu Besar) , and thence southwards into the bay 

 near Dindang, presents nothing remarkable, and therefore 

 does not appear especially to be recommended, we must say 

 the direct contrary of the Strait of Mindanao. By the kind- 

 ness of the Resident of Billiton, M. Zyip, I obtained for a 

 fortnight the use of a large vessel with a Malay crew of 

 seven men. During this time I dredged continually, and T 

 have never seen so many different forms, especially of Echi- 

 nida and Holothurida ; many Ascidia and Corals also occurred, 

 and among the latter I found the animal now under consider- 

 ation, Polyparium amhulans. Once, as I was examining the 

 booty brought up by the dredge, I found a yellowish-grey 

 slimy mass, the size of a chestnut, which consisted of spiral 

 convolutions and was beset with small tubercles. When I 

 isolated this body in a glass vessel I soon saw that the convo- 

 lutions separated and the mass spread into a band-like, rather 

 thick body, while the tubercles became small, mouth-like 

 apertures, and the whole body, to my great astonishment, 

 extended itself and began to creep slowly upon the bottom of 

 the vessel. 



When I turned the animal, or, more properly speaking, 

 the colony, so that the tuberculiferous back was downwards 

 and the creeping sole upwards, I found to my surprise that 

 the whole sole was covered with small acetabula ; thus it 

 appeared that the movement, the creeping of the colony, 

 results from the action of the acetabula. By a careful 

 observation of the creature I arrived at the following results. 

 It isa band-like body (PI. XIII. tig. 1), 7 centim. in length, with 

 a breadth of about 2*5 millim. and a thickness of perhaps '8 

 millim. ; the anterior and posterior extremities are exactly 

 alike, and rather pointed than rounded off. The lateral mar- 

 gins of the, colony are different in this way, that one of them 

 is strongly marked and bordered, so that it forms a very 

 perceptible boundary between the back and the sole, while 

 the other has no border ; but here the back is rounded and 

 cylindrical, and passes immediately over into the sole. Upon 



* Zool. Anzeiger, no. 223 (1886). 



