ANGELINA SBDGWICKI. 113 



outwards and backwards to the posterior margin, which they cut about half-way 

 between the axial furrow and the outer margin. Fixed cheeks nearly flat, with a 

 broad frontal limb in front of the glabella ; free cheeks wide, gently arched down- 

 wards. Head surrounded by a narrow raised rim separated by a marginal furrow, 

 which in front of the glabella bends slightly backwards, and is there marked by 

 a number of small close-set punctations ; marginal furrow continuous posteriorly 

 with the shallow occipital furrow. Genal angles produced into long and strong 

 spines continuing the curve formed by the outer margin and running almost 

 straight backwards to about the tenth thoracic segment. Hypostome subquadrate, 

 consisting of a central convex portion surrounded by a rather broad margin, which 

 appears to be toothed at the posterior angles. 



Thorax consisting of fifteen segments. Axis moderately convex, tapering very 

 regularly backwards, forming less than one-third the total width in front and less 

 than one-quarter posteriorly ; extremities of the axial rings somewhat nodular. 

 Pleurae flat near the axis, bent downwards, and a little backwards, at the fulcrum, 

 which is placed more than one-third of the way out in the anterior segments, less 

 than one-quarter in the posterior segments ; obliquely grooved ; faceted ; extre- 

 mities falcate, and in the later segments produced into short spines. 



Tail small, approximately semicircular, spinose. Axis convex, occupying less 

 than one-third the total width, ending bluntly some distance in front of the 

 posterior margin, showing three rings besides the articular surface and the rounded 

 terminal portion. Lateral lobes gently arched downwards, consisting of two 

 segments similar to the posterior thoracic segments fixed to a rounded terminal 

 plate, the points of the fixed pleura? projecting as two short, but well-defined, 

 spines upon each side. 



Dimensions. — As in most common species, the size varies considerably, but 

 8 cm. may be considered a medium length. The specimen figured on Plate XIII, 

 fig. 7, must have been at least 11 cm. long before distortion. 



Perhaps the most useful diagnostic character of the species is the total absence 

 of any definite glabellar furrows and the faintness of the neck-furrow. Some 

 specimens, indeed, with the light in certain directions, show very shallow ill- 

 defined depressions, which may represent glabellar furrows, but they are always 

 vague and indefinite ; and this is true both when the actual test is preserved and 

 in the much more common case of internal casts. In Beltella the outer surface of 

 the test is, apparently, devoid of definite glabellar furrows, but on the internal 

 cast the furrows are often quite distinct. B. verisimilis is the species which most 

 nearly approaches Angelina in this respect ; but it may be distinguished by the 

 more forw r ard position of the eye, the smaller number of thoracic segments, and 

 the greater relative width of the axis. 



Internal casts of Angelina sedgivicki, when well preserved, show the anterior 



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