392 AllxDiji J^iisnt/ii RfTords. 



PHACOPID.^, Salter. 



Phacops criHta-galli, Woodward. 



PI. X., Fig. H. 



There are two tine plastei' casts of the original in the Albany 

 Museum fi'om whicli I figuie the part of the head seen from 

 above, to enable one to compare this species with the other 

 Pliacops. Lake figures a specimen collected by me in Gamka 

 Poort as this species^ but I can see no resemblances either with 

 the plaster cast or with Dr. Woodward's fignre. According to 

 Lake, the Gamka Poort species " exactly' resembles the specimen 

 described by Dr Woodward, except that the tuberculation is much 

 less distinct, the axial spines are shorter, and the tail is not pro- 

 duced into a long mucro but only into a short point. From these 

 characters we may conclude that it is a younger specimen." As 

 the external casts of Phacops acacia show all the characters of the 

 Gamka Poort species without reservation, the latter form must be 

 placed in this species, and will piobably be referred to P. africa- 

 nus when the doubts that I raise when describing P. acacia, have 

 been settled. I agree wholly with Lake that P. crista-gaUi is 

 different from P. c(,rbufetis, if the pygidium which Lake figures 

 does really belong to the latter species. In P. crista-galli the 

 sides of the tail are marked with strongly convex ridges ; the first 

 four bear three very prominent tubercles, probably the bases of 

 spines, the fifth is curved backwards near the margin, and bears 

 two tubercles, the sixth is almost obsolete, but bent backwards in 

 a sigmoid curve, and bears still two tubercles, while the seventh 

 is faintly raised above the surface of the broad base of the tei'mi- 

 nal spine. The spine is curved upwards and is uniform in thick- 

 ness thioughout its length of 1.2 centimetres. The axial spines 

 are a little over one centimetre in length reckoned fiom the back 

 of the next segment behind. The rings are very swollen and the 

 tuberculation very prominent in contrast with the flattened rings 

 of P. acacia and Lake's P. crii^ta.-galli. 



Locality, Cockscoml) Mountains, along with Pirtetus ricardi, 



'Ann. 8, A. Museuiu, Pt. IV, Vol. IV., 1904, p. 205, PI. XXIV, fig. 5. 



