314 Dr.F. R. Cowper Reed — The genus Homalonotus. 



Y. — Notes oisr the genus Homalonotvs. 



By F. E. Cowper Eeed, Sc.D., F.G.S. 



{Concluded from the June Number, p. 276.) 



6. Burmeisteria, Salter, 1865. 

 rpHE type of this section is the Lower Devonian species JS'oinalonofns 

 X Herscheli (Murchison) ^ from South Africa and the Palkland 

 Isles.* The characters of the section were stated by Salter to be as 

 follows: " Elongate, convex; head triangular, eyes approximate on 

 gibbous cheeks. Glabella distinct, lobeless, spinous. Thorax slightly 

 lobed and spinous, as is also the many-ribbed pointed tail." It 

 should at once be stated that the type-species has neither a lobeless 

 nor a spinous glabella, and Salter apparently added in these characters 

 from the Rhenish H. armatus, Burni., which he included in the 

 section. The only Britisli form quoted by Salter is one from Devon- 

 shire based on a pygidium which does not conform to the above 

 definition and was described under the name IT, elongatus.'^ 

 Woodward,* in reviewing the Devonian species of Homalonotus, 

 follows Salter in inclading the latter species in Burmeisteria. 



The course of the facial sutures in S. Herscheli is important ; they 

 bend in rather suddenly in front, so as to form a transverse, gently 

 arched or sinuated commissure and meet in the middle at a very 

 obtuse angle. The pre-glabellar area is large, but the pre-sutural 

 area is very narrow, as in H. Knighti. The parallel epistomal 

 sutures arise nearly at right angles to the transverse commissure, 

 and cross over the margin to the inferior surface. The epistorae itself 

 has a median apiculus projecting in front of the margin of the head- 

 shield, which is otherwise subtruncate. Lake's species H. colossus,^ 

 also from the Bokkeveld Beds of South Africa, is represented as 

 possessing a similar epistomal projection, and in the Brazilian 

 species H. noticus, Clarke,* it is also developed. 



It can hardly be doubted that Salter included more than one 

 species of Homalonotus under the one specific name H. Herscheli, 

 though Clarke (op. cit.) seems inclined to question it. Lake (op. 

 cit.) and Schwarz^ have established several new closely allied species 

 from the same South African beds, and an examination of Salter's 

 original types, now in the British Museum, has convinced me that 

 H, Herscheli admits of division. The typical form is shown by the 

 head-shield (No. 11276) illustrated in his figure la, h, c; this 

 specimen comes from the locality Leo Hoek and has a transverse 

 shape, a distinctly lobed glabella, and no coarse tubercles or spines on 

 the surface, except two or three small ones on the pleuro-occipital 

 ring, the general surface of the head-shield being merely ornamented 

 with almost equidistant, widely spaced, coarse granules. The facial 



^ Salter, Trans. Geol. Soc, ser. ii, vol. vii, p. 215, pi. xxiv, figs. 1-7, 1856. 



2 Clarke, Foss. Dev. Parana, 1913, p. 93, pi. iii, figs. 1-4. 



2 Salter, Man. Brit. Trilob., p. 122, pi. x, figs. 1-2. 



* Woodward, Geol. Mag., Dec. IV, Vol. X, p. 29, 1903. 



^ Lake, Ann. S. African Mus., vol. iv, pt. iv, p. 216, pi. xxvi, fig. 1, 1904. 



^ Clarke, op. cit., p. 89, pi. i ; pi. ii, figs. 1-13. 



■^ Schwarz, Eec. Albany Mus. S. Africa, vol. i, No. vi, pp. 382-91, 1906. 



