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66 MR. F. W. 0. RYMER JONES ON SOME JATAN DEEP-SEA LAGEN.E. 



sometimes compressed. The second chamber encloses the anterior portion of the primor. 

 dial one, into which the latter opens by a rery " sessile" and wide central aperture. Tliis 

 orifice, however, may be provided with a short-lipped neck. The second chamber is 

 generally very large and flask-shaped or globose, the walls being sometimes very bul 

 and produced at the anterior end into a long, central, more or less slender stolon tube 

 The aperture is sometimes dentate, or is encircled by a smooth lip, the outer margin 

 which is occasionally " scalloped 



The form depicted in fig. 60 appears to be more allied to the marginate series, the 

 primordial chamber being lenticular, compressed, and surrounded by a well-developed, 

 thick marginal keel, terminating on each side of the aperture, which is central, " sessile," 

 and inside the second chamber. This second portion is also slightly compressed, embracing 

 the primordial one at about its anterior fourth. In outline it is somewhat bottle- 

 shaped, tapering forwards into a weU-developed neck, which swells out shghtly at the 

 apex, where it is largely dentate. 



This chamber is somewhat bent out of the axial Hne, and is not unlike a champagne- 

 bottle— a simile which the dentate aperture rather strengthens. 



Along the two sides of the neck also extends a transpai-ent ridge, which, however, is 

 more developed on one side than on the other, and is soon lost in the shell-walls, which 

 are semitransparent, white, and densely forammated. These canal pores are differently 

 disposed in the two chambers, those of the larger one passing directly from within out- 

 wards, while those of the primordial chamber take a radial direction, similar to the form 

 depicted in fig. 33. . ■ 



A double-chambered Lagena is represented in fig. 61, the primordial one of which is 

 provided at its base with a small central mucro. The walls are finely foraminated and 

 ornamented with about fourteen deHcate longitudinal riblets. A little above the middle 

 it becomes enclosed by the second chamber, into which it opens through a stumpy neci 

 This portion of the structm^e is much larger, presenting the appearance of a very bulging, 

 symmetrical, smooth flask, passing at the anterior end into a weU- develop ed nect, wMcli 

 in this example is somewhat broken. The walls of this flask are also finely perforated, 

 but, unlike the primordial chamber, are perfectly smooth and ribless. 



Fig. 62 closely resembles fig. 61 in ^general outHne-the upper flask, however, being 

 much more bulged, and the neck more fully developed and lipped at its termination. 

 Ihe external margin of this rim is also prettily "scaUoped," and the neck-walls orna- 

 mented with a few minute and feeble tubercles scattered over it. . , 



ihe primordial chamber is somewhat compressed, and encircled by a thick margmal 



^eel, which bears a smaU mucro at the centre of the base. The inferior portion of this 



hamber is decorated with a few feeble riblets, which are very rudimentary, and coafinj 



delwT; ^.^^^^^^^ «^-^ber, however, is ornamented with about fourteen weU- 



i^UT '''"'"^ ^^^ ^^^^y foraminated ; but in the primordial one th^ 

 Eetfrir""? 'f ^ "'^^^^^^^^ ^ ^^- -V (tbo e occupying the central partj^^ 

 Cher It^^^^^^ P-«-^- d-ctly from witlun outwards. The primo^^ 



chamber appears broken short immediately after entering the base of the anterior one. 



I 

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