385 



front, which is broadly rounded ; glabella furrows in two 

 pairs, the first pair all but circumscribing the basal lobes; 

 axial furrows deep and well marked. Neck lobe in comparison 

 to the size of the glabella broad and large, its furrow par- 

 ticularly deep. Fixed cheeks, only partially preserved, but 

 apparently wide. Surface minutely granular. 



Ohs. — The replicas do not display any traces of the facial 

 sutures, ocular ridges, or eyes, nor is there any trace of the 

 oblique striae "seen on the cheek in advance of the eye which 

 spread from it to the anterior border of the glabella." The 

 space occupied by an eye "on the anterior half of the head," 

 as well as that by the oblique striae, appear to me merely 

 as fractured matrix surfaces. 



Loc. — Yorke Peninsula, South Australia (Woodward). 



Hor. — Parara jLimestone, Lower Silurian (Woodward) ; 

 Lower Cambrian (Tate) ; Upper Cambrian (Howchin) ; Cam- 

 brian (Etheridge). 



Ptychoparia ( ?) howchini, Eth . fil. 



PI. xl., fig. 7. 



P. howchini, Eth. fil.: Trans. Roy. Soc. S. Austr., xxii., 1888, 

 p. 2, pi. iv. 



Obs. — At the time I described this imperfect cephalon 

 I compared it with Woodward's ' 'C onocephalit es australis," 

 but relying on the supposed accuracy of the figures given, 

 believed them to be distinct. I now find the general aspect 

 of the glabella of P. howchini to so closely resemble that of 

 the replicas of Woodward's species that suspicion is raised of 

 the identity of the two ; but like so many other questions con- 

 nected with these Cambrian Trilobites, this possibility must 

 remain in that sense only for the present. 



Loc. — Ardrossan, North-east Yorke Peninsula (Howchin). 



Hor. — Lower Cambrian, or "Olenellus Group" (Tate); 

 Upper Cambrian (Howchin) ; Cambrian (Etheridge). 



Ptychoparia alroiensis, n. sp. 



PI. xl., fig. 8. 



Trilobite cast., Anon. : Bull. N. Territory, No. 14, 1910', 

 pis. ii. and iii. 



Sp. Chars. — Cephalon semicircular (when perfect). 

 Glabella obtusely conical, rounded in front, separated from 

 the fixed cheeks and anterior limb by well-marked deep axial 

 grooves; two pairs of furrows, the basal pair circumscribing 

 prominent basal lobes; fixed cheeks comparatively large, but 

 less convex than the glabella; palpebral lobes small, the con- 

 necting eye-lines, or ocular ridges, situated just in advance 

 of the anterior pair of glabella furrows, anterior limb like the 



N 



