388 Transactions of the Society. 



observations go. It occurs rarely in a rich foraminiferoiis mud 

 dredged by the ' Goldseeker ' in the North Sea (Haul 145, Station 

 IXb, depth 330 metres), and an occasional specimen is to be found 

 at adjacent stations, especially Station IX (61° 34' N"., 2° 4' E., 

 390 metres). No specimen has yet been found showing definite 

 initial or final portions of the tube, all being more or less frag- 

 mentary; but the fact that nearly all the fragments were living 

 when dredged, as was proved by the presence of protoplasm in the 

 tube, seems to show that the tube may grow indefinitely, and 

 that injuries to the extremities of the tube do not affect the life of 

 the animal. The tube is doubtless flexible when living, like 

 Bathysiplion filiforjnis (Sars). The fragments vary from 1-4 mm. in 

 length. The average external diameter of the tube is • 08 mm. 



Marsvpella cylindrica Brady. 



Marsipella cylindrica, Brady, 1884, Foram. ' Challenger,' p. 265, pi. xx. 



figs. 20-22. 



This species was described and figured by Brady from specimens 

 dredged by the ' Knight Errant ' in the warm area of the Faroe 

 Channel, 530-542 fathoms. He describes his specimens as tubes 

 of tolerably even diameter, rarely exceeding ^-in. in length, and 

 varying from 2oo~Ton i^* ^^ breadth, " manifestly only portions of 

 an organism that might be continued almost indefinitely." 



The species is abundant in most of the deep-water dredg- 

 ings made by the ' Goldseeker ' in the Faroe Channel and also at 

 Station IX in the North Sea. But when dredging to the west of 

 St. Kilda in 1910, Earland discovered the perfect organism, which 

 we take the present opportunity of figuring. 



As figured by Brady the tube of Marsvpella cylindrica is open at 

 both ends, but in perfect specimens the oral extremity terminates 

 in a club-shaped head of loosely aggregated sponge spicules, from 

 which a number of long spicules • 5-0 • 8 mm. in length radiate in 

 all directions. The club-shaped head is from two to three times the 

 diameter of the tube ; the tube often reaches over |-in. in length. 



The spicules forming the knob are not cemented together or to 

 the tube, but are merely felted together and are easily broken 

 down. This no doubt explains why the test is so seldom found in 

 a perfect condition. It is very probable that other Foraminifera 

 may present a similar terminal appendage when living. 



The purpose of the club-shaped head or knob is not very appa- 

 rent, but probably it serves two purposes. The aggregation of loose 

 spicules closing the mouth of the tube will prevent the ingress of 

 worms and other predatory animals, while the longer spicules may 

 serve the double purpose of defensive spines and " stays " to support 

 the radiating pseudopodia in their quest for food. As the tube 



