342 F. R Coiuper Reed— 



and of a non-annulated smooth posterior part beyond the base of 

 the seventh pair of lateral pleurae, which is imperfect and only 

 10 mm. in length, but seems to have measured about 20 mm. There 

 is a pair of small tubercles or spines on the first axial ring, and also 

 on the third, fourth, fifth, and sixth, and possibly on the seventh, 

 but not on the other rings. The articulating half ring at the front 

 end of the axis is marked off by a strong furrow, which is continued 

 on to the lateral lobe, so as to separate off a large triangular 

 articulating surface from the first pleura. The pleural lobe, which 

 is perfect, shows seven pleurae, but the seventh one is very small. 

 The pleurae are broad, low, and flattened, and the first one carries 

 a large low tubercle at about half its length (or rather more), while 

 the fourth pleura has a similar tubercle at about one-third its length, 

 thus resembling H. bifurcatus. The other pleurae are smooth. There 

 is a smooth border of regular width round the pygidium, for the 

 interpleural furrows do not reach the margin. The other smaller 

 specimen has the same general characters, but seems somewhat 

 more elongated, and there are no tubercles visible on the pleurae 

 or axis, but this may be due to immaturity or to individual 

 variation, if we consider that Clarke ^ has made out his case for 

 a similar variation in the allied tuberculated sjoecies, H. Herscheli 

 Murch. 



An imperfect glabella from New Cut, in the Sedgwick Museum 

 (S. 8), measuring about 20 mm. in length, shows the lateral tubercles 

 and the anterior median one, but the posterior part of the glabella 

 is missing, and nothing of importance can be added to Woodward's 

 description. There is, however, an interesting thoracic ring (S. 4) 

 from the same locality and in the same collection which retains 

 one of the pair of spines on the axis in an unbroken condition — 

 a most unusual circumstance. The width of the axis in this specimen 

 is 38 mm., according to the dimensions of the one perfect side, 

 and the distance between the spines at their base is 22 mm. The 

 complete spine rises up suddenly from the surface, and is directed 

 obliquely outwards -', it is straight, cylindrical, and slender, tapering 

 regularly to a sharp point, and its length is 18 mm. 



Another thoracic ring (S. 4a), with the axial spines 32 mm. apart, 

 from the same locality and in the same collection, shows clearly the 

 broad, flat articulating band on the front edge, nearly as broad in 

 the middle as the ring itself, but near the axial furrow or constriction 

 decreasing slightly in width. The strong, sharply impressed groove 

 which marks it off from the ring is continued on to the pleura on 

 each side so as to become the pleural furrow. The outer portion and 

 tip of one pleura (S. 7) from the left side of the thorax shows this 

 so-called pleural furrow well. This pleura has a flattened and rather 

 rapidly broadened subspatulate extremity, with the anterior edge 



1 Clarke, Fos^s. Dev. Parana (Mon. Serv. Geol. Miner. Brasil), vol. i, p. 93, 

 pi. iii, figs. 1-4. 



