PROETUS. 25 



4. Proetus audax, Whidbome. PI. II, figs. 5 — 10. 



1841. Calymene granulata (pars), Phil. Pal. Foss., p. 128, pi. lvi, fig. 248, 



m and o only. 

 1889. Proettts audax, Whidb. Geol. Mag., dec. 3, vol. vi, p. 29. 



Description. — Contour very tumid. Glabella large, very prominent, heart- 

 shaped, without indentations, narrowest in front, nearly equal in length and depth, 

 reaching or overhanging the border, but separated front it by a deep linear 

 groove; coarsely tuberculated, the tubercles being largest behind. Border rounded 

 in front, with strong ridges continued to the posterior angle. Fixed cheeks 

 swollen, rising between the border and glabella, much elevated at the eye-lobe. 

 Suture slightly oblique in front ; free cheeks with two or three rows of sharp 

 tubercles. Eye very large, elevated, smooth, and nearly round, situated in the 

 centre of cheek close to glabella. Latero-posterior angle rounded. Neck-furrow 

 long, narrow, and straight, continued on the cheek to the genal angle. Neck -lobe 

 very long, narrow, and bow-shaped, with two rows of tubercles. Hind margin of 

 cheek tuberculated. 



Pygidium. — Yery convex; axis broad, elevated, terminating a little before 

 the border, with rings irregularly tuberculated ; four or five ribs visible on the 

 limb, with rather deep central grooves, disappearing at a distance of about one- 

 third from the margin, at which the pygidium becomes slightly elevated. Border 

 with several strong ridges, seen especially behind the axis. 



Size. — A detached glabella in my collection measures 9 mm. in leDgth, 11 mm. 

 in depth. 



A tail measures 9 mm. in length, 14 mm. in width, 6 mm. in depth. 



Locality. — Lummaton. I have obtained ten specimens of the glabella, one of 

 the cheek, and six of the tail. There is a similar glabella in the Torquay 

 Museum, and another in the Bristol Museum. 



Remarks. — The evidence of this species, though not scanty, is very fragmentary. 

 The glabellas that I have seen are generally in bad condition ; and, as all the heads 

 and tails of Trilobites found at Lummaton are detached, there is always room for 

 question as to the correctness of the specific identification of the two parts. In this 

 instance I have been chiefly guided by some specimens of P. Isevigatus (Goldf.) 1 in 

 the British Museum. To these fossils it is very similar ; but its larger size, the 

 absence of small cheek-spines, the width and ornamentation of the neck-lobe, the 

 ornamentation of the pygidium, and the absence of a furrow on the cheek present 

 differences. To that species, as figured by Goldfuss, it bears a very close resem- 

 blance, being, however, distinguishable by the coarse granulation visible both on 

 1 1843, " Qerastos Icevigatus" Goldf., ' Neues Jahrb.,' p. 557, pi. iv, figs. 3 a, b. 



