144 G. F. MATTHEW : ILLUSTRATIONS OF 



lorum parvorum ornatœ. Pygidium parvum duplo latins quam longius, costis lateralibus 

 utrinqiie binis, duplicatis. 



" The head-shield, which, iu its natural condition, is convex, is commonly more or less 

 flattened in slate. The glabella is strongly convex, considerably overtopping the remainder 

 of the head-shield ; it is oval, with the length but little greater than the breadth ; more or 

 less outdrawn, roimded toward the front ; on each side provided with three obscure 

 furrows. The neck-ring widens in the middle, and is provided with a point, which is 

 wanting in examples deprived of the crust [or test] and even on a large number with the 

 crust it cannot be observed, but still always may have been found with complete examples ; 

 even those which have not the point preserved, shew on the back edge [of the neck-ring] 

 where it has been broken off. The dorsal furrows are narrow and not deep, but plain, 

 and bend round the glabella, making a regular curve. The fixed cheeks are evenly and 

 regularly elevated, and join in front of the glabella by a narrow outward-ending limb, 

 into which they connect without any sharp limit. This limb has a somewhat variable 

 breadth. In some examples it is equal to a third of the length of the glabella, in others 

 it is about a fifth of that length. The anterior edge of the head-shield is flattened, 

 widened in the middle and commonly somewhat descending at the outer ends, although 

 inconsiderably, and less than the limb [of the cheeks] lying behind it. The eyes are 

 rather small, and situated about midway between the front and back margins of the 

 head-shield ; they are joined to the glabella by a more or less distinct, oblique-goiug, 

 ocular fillet. Their distance from the glabella is greater than half of its breadth. The 

 average length of the head-shield [from several localities] would be about 8 mm. and the 

 breadth within the sutures 12 mm. 



" Some quite small examples in the collections of the G-eological Survey [of Norway], 

 show the forward part of the thorax. The illustrated example has nine joints. The 

 rachis is small, slowly narrowing backward. The pleurae are broadly furrowed and have 

 the inner part horizontal, the outer gently curved down, but are iu projection almost 

 straight. So far as one can see from this example, and even from single loose thoracic 

 joints, their ends are bluntly rounded off, not lengthened into a point, as is the case with 

 L. viicrophtlialmiis, which besides, according to Brogger's description and figures, like some 

 examples from Andrarum, is distinguished by having the ninth [joint] considerably 

 longer than the others. The illustrated example lacks the crust, and shews no sculptures. 

 In some separate pleurœ [of L. Linnarssoni] from Andrarum and West Gotland, one finds 

 that each side of each longitudinal furrow carried a row of extremely fine tubercles. The 

 same character is exhibited in an impression (of the crust) from Krekling; it shews even, 

 that each joint of the rachis was guarded by a spine, and had besides, on the back edge, a 

 row of fine tubercles. The Geological Museum at Lund contains a complete example 

 found just above the slate with Agnoslns intermedius. The thorax, whose joints are partly 

 displaced, contains, so far as one can see, thirteen segments. The corresponding impres- 

 sion shews that the pleura had a row of fine tubercles on each side of the longitudinal 

 furrow, and that even the rachis joints have been ornamented with such tubercles ; but 

 it shows no sign of a spine on the neck-ring, or the rachis of the thorax. 



" Only a few examples of the pygidium of this species, differing a little from each other, 

 are to be found among the collections of the Geological Survey [of Norway]. They are small 

 and almost lens-formed, with a breadth more than double their length. One example from 



