1068 NOTES ON AUSTRALIAN FOSSILS, 



figure, a ring of smaller tubercles on an elevated surface, from four 

 to eight in number, around each of the four prominent ones 

 (fig. 5 bis). 



Now I come to the supposed articulation between the axis and 

 the pleurae as shown in our specimen. 



Nearly fifty years ago, Emmrich in " De Trilobitis Disser- 

 tatio, &c." was of opinion that such an articulation existed, and he 

 mentions Ogygia Buchi, and C onocejihalites Sulzeri. Burmeister 

 combated that opinion, and Barrande confirmed the views of the 

 last except in the case of Arionellus cetice])halus (I.e., p. 166, pi. X.> 

 fig. 16.) 



However, one cannot help being struck in examining the specimen 

 in question, at the great resemblance to an articulation of the 

 junction of the axis with the pleurae. It seems as if the test (or its 

 different joints) had been covered by a thin epiderm as admitted 

 by Burmeister (Barrande I.e., p. 231), and that this epiderm is 

 wrinkled at the articulations as shown in fig. 5, and especially in 

 the enlarged sketch, fig. 8. 



Locality : Bowning. 



It may be added that A. Verneuili is included by Barrande in 



his " Etage E, Faune III," and A. vesiculosa in his "EtageF, 



Faune IV." 



Acidaspis Verneuili. 



(Plate XV. fig. 10.) 

 This species is also represented by a small pygidium 9 mm. in 

 width, corresponding to a specimen 26 mm. long, the spines 

 excluded. It has seven barbed spines. 



The following specimens are more doubtful. 



(Plate XV. fig. 11.) 

 A head with part of thorax corresponding to a specimen about 14^ 

 mm. in length, measures 1 2 mm. across from the origin of the genal 

 points, and only 4 mm. from the front to the border of the occipital 

 ring ; it is therefore three times broader than long. This character 

 corresponds with broad cheeks and prominent eyes, and suggests 

 A. Prevosti, (Barr. pi. 39). The occipital spines, however, are not 

 seen. 



