210 Amwls of the SovtJi African Miisevm. 



It is easily distinguished from Phacopn ocellus by its more 

 depressed form and the character of the glabellar furrows, and also 

 by the fact that the tail axis is pointed and bears a larger number of 

 rings. 



Loccditics.—Gumkii Poort (35, 43, 44, 47, 48, 49, 50, 51, 'r2, 54, 55). 



PHACOPS (CKYPH/EUS) CAFFEE, Salter. 



Plate XXV., figs. 3, 4. 



J8[)C). Fliacops (Cnjplia'vs) coffer, Salter, Trans. Geol. Soc, ser. 2, 

 vol. vii., p. 219, pi. XXV., figs. 10, 11, 12, not 13. 



Of the form which is here described the collection under descrip- 

 tion includes an imperfect head and several tails, two of which have 

 thoracic segments attached to them. On the same block as the 

 head there is a somewhat incomplete tail which resembles exactly 

 the tails (from the same district) to which the thoracic segments are 

 attached. There can, I think, be little doubt that these fragments 

 belong to the same species. 



The specimen of the head shows only the glabella and the fixed 

 cheeks. The glabella widens rather rapidly in front, and is sepa- 

 rated from the cheeks by deep axial furrows ; the frontal lobe is 

 large and swollen ; glabellar furrows well defined, the first being 

 deep and inclined forwards, the second pair also fairly deep but 

 short and not reaching the axial furrows ; the third pair stands at 

 right angles to the axis. Ej'es small, near the glabella, reaching 

 from the first glabellar furrow nearly to the middle of the second 

 lobe. Neck furrow well defined throughout, occipital segment 

 smooth. 



Thorax depressed. The axis occupies just one-third of the width, 

 and tapers rather rapidly. The pleurae form an elbow at a point 

 rather more than one-third of their length from the axis, and are 

 deeply grooved, the groove being strongest at the elbow and dying 

 away exteriorly ; the ends of the pleurae form strong points. 



Tail depressed ; width about twice the length. The axis is but 

 slightly raised and barely reaches the posterior margin, diminishing 

 rapidly in width up to the fifth ring ; ten or eleven rings are visible 

 in all, of which the last four are indistinct. The lateral lobes bear 

 five distinct ribs besides the articular ridge, and these are separated 

 by strong furrows ; each rib, except perhaps the last, is grooved 

 along its whole length, so that the segments of which the tail is 



