﻿MR. F. W. O. RYMER JONES ON SOME JAVAN DEEP-SEA LAGEN^. 59 



layer of semiopaque shell-substance, wMcli in fig. 38 is also finely granulated, thougli 

 to a less degree tlian the shell-walls proper. 



In the lenticular form (fig. 38) the internal tube extends nearly to the bottom of the 

 cavity, and passes out at its upper part, forming a short external canal embedded in the 

 outlying film, and widens out at the aperture, where it becomes lipped. The marginal 

 lamina appears to be double, being formed by two layers which are united like the mem- 

 branes of a leaf, and passes down the upper part of the shell in a wide even band. In 

 fig. 38 this regularity of outline suddenly ceases round the basal half of the periphery, 

 the marginal layer becoming irregularly and deeply ro welled. 



liAGENA vTJLGAUis, Williamson, var. bracteato-marginata, Nov. (Figs. 10, 41.) 



Shell subspherical, somewhat compressed, entosolenian, the tube passing to the ex- 

 treme base of the cavity, where its free end becomes patulous. Anteriorly (he tube 

 passes out of the flask to a variable distance, resembling more a canal than an external 

 neck, as it is still embedded in the shell-substance. Around the periphery project tlircc 

 or more wide lamelliform plates of great transparency, parallel to each other, though 

 quite distinct, the middle one often being the most prominent. Tlic marginal burdcr of 

 those layers is tolerably even at the apertural end of the shell; but it becoines very 

 irregular round the basal half, where these filmy plates sometimes become so translucent 

 that it is often difficult to follow their outline, and to count with certainty the number 

 of " plates." The lateral walls of the shell are also sometunes furnished with a greater 

 or less number of trenchant riblcts, as in fig. 40, whore there are three on either side. 

 In this form the walls are whitish, semitransparent, and coarsely foraminated, wJiil 



{• 



others are more opaque, and of a light brown tint. 



Fig. 41 differs considerably frok the preceding sheU, being very smooth and glassy, 

 while the walls are apparently imperforate. The marginal plates are about four m 

 number, and are laid side bv side more compactly than in the above-mention od examples, 

 and pass round the periphery with more regularity and evenness throughout, the scrmtcd 

 portion being more regular, and confined to the extreme base. Around the margin of 

 (and immediately on) the shell-wall is also an additional narrow flattened ridge, which 

 becomes lost in the walls at the upper part ; while at the extreme base, on each side, pro- 

 jects a thin pointed spine, similar to that observable in fig. 37. 



Lagena vulgaeis, Williamson, var. spinoso^marginata, Nov. (Figs. 42, 13.) 



Shell subglobular, lenticular, or ovoid, smooth, densely fornminat^d External n^^k 

 long, straight, and naiTOW, passing abruptly from the upper end of tlie structure and 

 patulous, lipped, and sometimes "scalloped" round it. ^^^^ 

 margin of the shell is ornamented with a wide smgle or double la>cr ol sJ eU 

 which passes two thirds up the neck, and becomes incorporated m its walh. 

 ^his band is single, and of film-Uke transparency, and is strengthened by a series of lon^, 

 slender, straight spines, which radiate from the circumference of the shell, and form a 

 single and paraUcl row round the flask. At the middle of the base these .pines become 



In fi - 42 



