LAGENA. 121 



LAGENA HOWCHINIANA, nov. PL X, figs. 1 5. 



Characters. Shell sub-spherical, oval, or flask-shaped, often unsymmetrical ; with 

 more or less strongly marked parallel longitudinal costue, along the top of which at 

 regular intervals are well-defined perforations. Neck short, often irregular. Orifice 

 wide. Length ^ to -^ inch. (0'4 to 0'5 mm.). 



As the most striking of the Carboniferous Layerus, it is manifestly proper, for reasons 

 I have already stated, that this species should be named after the Rev. W. Howchin. 

 It is a well-marked form, not likely to be mistaken for any other hitherto described. 

 The costse do not appear to be exogenous ribs as in many similarly ornamented 

 Foraruinifera, but are formed by crenulations of the shell-wall ; and the ridge of each 

 of the crenulations is pierced by a series of small orifices placed at regular intervals. The 

 perforations are sometimes obscured by infiltration, but their existence can nearly always 

 be detected. The test itself is thicker than is commonly seen in the Lagena, and its 

 surface is nearly always somewhat rough or granular. These characters, in addition to 

 its frequent irregularity of growth, render it in so far an anomalous member of the genus. 

 Double specimens, such as fig. 4, are occasionally found, but similar monstrosities occur 

 in many other species, both recent and fossil. 



Distribution. Found in the Bottom Limestone at Ridsdale, and in the shale 

 overlying the Great Limestone at Fourstones both Northumbrian localities. Its 

 occurrence in the Scottish Carboniferous Limestones is as yet noted in only a single 

 position high up in the series. 



LAGENA LEBOURIANA, nov. PL VIII, fig. 6. 



Characters. Shell sub-spherical or pyriform; having a surface ornamentation 

 consisting of a few, usually four or five, regular costse, proceeding from the base 

 to the widest portion (about the middle) of the shell, where they are merged in a 

 more or less distinctly raised transverse ring. Length -j^ inch (O25 mm.). 



A singular form, quite distinct from L. semistriata of Williamson. The costse, 

 commonly only four in number and equidistant, impart a somewhat quadrangular aspect to 

 many specimens. Sometimes there is a well-marked, raised, transverse ring, similar in 

 thickness to the costae, round the widest portion of the test, and in these cases the ends of 

 the costse are united to it, thus dividing the surface of the lower half of the shell into four 



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