55 



we could perceive myriads of lively swimming specimens about our boat. 

 We now came to realize that we had beenrowing in a big sheet of swarm- 

 ing Enteropneusts. More than delighted with this sight, we collected 

 a bucketful of specimens — a task accomplished in but a minute. They 

 measured from three to fifteen cm in length. The belt-like zones of 

 this plankton varied from one to five metres in width and were in some 

 cases two metres in thickness. The animals were crowded in various 

 degrees ; at the thickest spot about fifty individuals in a cubic foot of 

 water, while in the thinnest only about ten in same. After nearly a 

 hundred yards' row, we came across another broader sheet of swimming 

 Balanoglossus. They were so thick that we could count nearly a hundred 

 specimens in a cubic foot of water. When the sun was up, this curious 

 plankton almost suddenly disappeared. On coming back to the shore, 

 we found to our great surprise a considerable stretch of the beach (one 

 metre in width) covered with the deep brown enteropneusts. Most of 

 the stranded specimens were mutilated, the post- hepatic region being 

 lost. They were naturally very sluggish out of their element; however 

 they still showed some movements to burrow into the sands with their 

 proboscis. The curious phenomenon took place also in the two follow- 

 ing mornings. It should here be noted that the individuals swam in 

 every direction, but were probably blown together into zones by winds 

 and carried away en masse by tidal currents. 



To the above observations the informations gathered from fishermen 

 may be added. They call this Balanoglossus »Binbo-mushi« (Pauper 

 worm). The swarming on the surface should take place on calm 

 nights during summer months, from August to the beginning of Sep- 

 tember (not every year, but often with an intermission of several years). 

 The floating animals are said to be speciali}^ lively for some hours be- 

 fore daybreak. They should usually live on the bottom of from five to 

 fifteen fathoms. 



Ike da hat das Tier, das den Gegenstand dieser merkwürdigen 

 Beobachtungen bildet, als Glandiceps hacksii (Mar.) bestimmt. Ich nehme 

 an, daß das auf Grund meiner Monographie geschehen sein wird, in der 

 ich auf die zuerst von Marion beschriebene und später auch von mir 

 nach einem Bruchstück eines erwachsenen Exemplares untersuchte Art 

 auch zwei sehr viel kleinere Individuen bezogen hatte, indem ich darin 

 eine Jugendform zu erkennen glaubte. Mit dieser letzteren hat augen- 

 scheinlich dann 1903 RamunniMenonein Exemplar eines bei Madras 

 gefundenen Olandiceps identifiziert, eine Bestimmung, die auch Ike da 

 acceptiert. Inzwischen habe ich indessen in meiner Bearbeitung der 

 Enteropneusten der Siboga, 1907, S. 98 ff., darzutun versucht, daß 

 wahrscheinlich sowohl Menons Art als der vermeintliche junge Gl. 



