FOKAMIXIFERA OF THE ATLANTIC OCEAN. 25 



The material discovorcd by Earland in the North Sea is very inter- 

 esting as giving much now data in regard to the structure of this 

 species. They ' are quoted at length in the following paragraphs: 



This species was descril)ed and ti^ured l)y Brady from species dredged by the Knujh t 

 Errant in the warmer area of the Faroe ( hannel, 530-542 fathoms. lie described his 

 species as tubes of tolerably even diameter rarely exceeding one-fourth inch in length 

 and varying from one two-hundredth to one one-hundredth inch in breadth, mani- 

 festly only portions of an organism that might be continued almost indefinitely. 



The species is abundant in most of the deep-water dredgings made by the Gold- 

 seeker 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 M. cylirulrica is open at l)oth ends, but in perfect 

 specimens the oral extremity terminates in a club-shaped head of loosely aggregated 

 sponge spicules, from whicli a number of long spicules 0.5-0.8 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 one-half inch 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 Foram- 

 inifera may present a similar terminal api>endage when living. 



The purpose of the club-shaped head or knob is not very apparent, but prol^ably 

 it serves two purposes. The aggregation of loose spicules closing the mouth of the 

 tube will present 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 grows in length the spicules 

 are absorbed and ])uilt into the wall of the tube, other spicules being collected to serve 

 in their place. 



Marsipella cylindrica, although a neat builder, does not show the skill and construc- 

 tive ingenuity of its relative, ^f. spiralis. Sponge spicules enter largely but not 

 entirely into its construction, being mixed indiscriminately with some sand grains, 

 mica, etc., in varying proportions. Individual specimens vary greatly in the neatness 

 of their construction, some showing a slight tendency toward a spiral arrangement of 

 the fragments. We figure one fragment in which this spiral twist is strikingly mani- 

 est. The absence of the cement which characterizes M. spiralis proves that *l.e frag- 

 ment should be referred to M. cylindrica and not to M. spiralis. Moreover the spiral 

 is right-handed. 



The question might arise whether the presence of the terminal club-shaped head in 

 M. cylindrica does not necessitate the transference of the species to a separate genus. 

 In view of the fact that the terminal portion is so loosely constructed that it can not 

 be said to close the tube, we see no reason at present for the transfer of the species. 

 We would, however, suggest that Norman's definition of his genus Marsipella, now 

 quoted,^ should be amplified by the inclusion of the words we have inserted in italics. 



Genus MARSIPELLA, n. g. 



fxapffiiros (a purse.) 



Test elongated, fusiform (or cijlindriml) centrally cylindrical and drawn out to 

 gradually attenuated extremities, open at both ends [or closed anteriorly by a loosely 

 aggregated knob of spicules] monothalamous; anterior extremity much produced into 



' Heron-Allen and Eartmd, Joiirn.Roy.Micr.Soe.,1912,p.388,pl.r),figs.8,9; pl.C,figs.8,9. 

 2 Norman, A. M., "On thogenu.s Haliphysemag, with description of several forms apparently allied to 

 it." Ann. Mag. Nat. Hist., ser. 5, vol. 1, p. 281. 



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