540 Transactions of the Soeietij. 



forms of recent times. The not unfrequent duplication, seen in 

 aberrant examples among recent Lagenx, may, perhaps, be instances 

 of reversion to type, as seen in the polythalamous examples of 

 Carboniferous times, and included in the present genuB. 



Archselagena Hoivchiniana, Brady, sp. Plate IX. fig. 18. 



Mr. Brady's description of the monothalamous examples of this 

 species is a very accurate one, and needs no adjustment. A more 

 extended acquaintance with this form has, however, shown that it is 

 much more commonly polythalamous than monothalamous in its habit 

 of growth. The chambers usually number from two to twelve, and, 

 in rare cases, even up to nearly twenty, and are irregularly grouped 

 around the axis of growth. The method of growth is apparently by 

 budding. The chambers differ greatly in relative size, and many 

 show more or less distortion in shape by compression through the 

 concurrent growth of adjoining segments. There may be one or more 

 general orifice to each group of united segments, the latter communi- 

 cating by interseptal apertures. 



Possessing the morphological and structural characteristics now 

 described, Archielagena Hoicchiniana can no longer be consistently 

 regarded as belonging to a genus which is essentially monothalamous. 

 On the other hand, Lagena Parheriaiut, and L. Lebouriana, although 

 exhibiting in test structure some points of resemblance to the forms 

 classed under the present species, have never been met with except as 

 single-chambered and free examples, and may therefore be left, at least 

 for the present, in the position assigned them by Mr. Brady. 



Distribution. — Not very common ; recorded in connection with 

 twelve washings from the following: — First Lower Felltop, at 

 Penpeugh ; at various localities and horizons of Great Limestone ; and 

 from the " D " Limestone of Tipalt and Cowburn, the last-named 

 hmestone being the best bed for the form. 



Genus Endothyea, Phillips. 

 Endothyra conspicua, sp. nov. Plate IX. fig. 12. 



Test nearly circular in lateral outline, compressed, slightly 

 asymmetrical bi-laterally, composed of about three convolutions, all of 

 which are more or less visible exteriorly. Segments inflated, sub- 

 globular, from ten to twelve in the outer whorl. Diameter of large 

 specimens 1/20 to 1/16 in. 



This is an interesting variety in which the usually embracing 

 character of the genus is but feebly developed. It has probably its 

 closest relationship with E. Bowmani, some examples of which exhibit 

 a considerable umbilical depression not embraced in the fold of the 

 outer convolution. It is, ho\\ever, easily distinguished from the latter 

 species, by its more circular outline, its more numerous and globular- 

 shaped segments, and, more particularly, in the exposure of the inner 

 whorls which are often visible throughout their entire convolutions. In 



