Dr.F. R. Coivper Reed — The genus Homalonotus. 325 



bent in suddenly near front margin and uniting in continuous transTerse 

 commissure. Pre-glabellar area "vrell developed. Glabella short, 

 subquadrate, or oblong. Thorax with trilobation usually distinct 

 and well marked. Pygidium triangular, elongated, acuminate, more 

 or less pointed behind, composed of many segments ; trilobation 

 generally well marked. Surface of thorax and pygidium occasionally 

 scabrous or tuberculated, but not spinose. 



Type. — H. gigas, Roemer. 



Range. — Lower Devonian. 



DiSTEiBUTiON. — Ehenisharea, France, ? England, ? Argentina. 



Examples. 

 H. rhenanus, Koch. H. Le Hiri, Barrois.^ 



H. scabrosus, Koch. ?iJ. goniopygmus, Woodw. 



H. ornatus, Koch. '> H. Kayseri, Thomas.^ 



Kemaeks. — The strange course of the facial sutures in their 

 transverse union is somewhat like that of Koenigia and Dipleura, but 

 the pygidium is closely similar to that of Burmeisteria. The triloba- 

 tion of the thorax is, however, more distinct than in the latter. 

 The shape of tlie glabella is unusual. We are not acquainted with 

 the true anterior margin of the head-shield, and know nothing about 

 the epistome. It is very uncertain if the common but imperfectly 

 known species^, armatus, 'Qurm.., belongsto this subgenus (see below). 



8. £urmeisterella, nom. prop. 



Head-shield subtriangular, produced anteriorly into upturned 

 prora formed by epistome and bounded by epistomal sutures. Pre- 

 sutural area large. Facial sutures bend in suddenly in front and 

 unite by transverse commissure close to anterior end of glabella. 

 Pre-glabellar area narrow. Thorax with well-defined cylindrical 

 axis, of less width than pleural portions ; trilobation distinct. 

 Pygidium semi-oval, rounded, with regular entire margin (in one 

 species provided with pair of short terminal spines) ; axis narrow, 

 elongated, distinct; composed of many segments; pleurae distinct. 

 Surface of glabella and of thoracic and pygidial axes ornamented 

 with regularly disposed pairs of large tubercles or spines. 



Type. — H. elongatus, Salt. 



Range. — Lower Devonian. 



Distribution. — Devonshire, ? Rhenish area. 



Examples. 

 H. Chaynpernoivnei, Woodw. 7 H. aculeatus, Koch.* 

 H. hifurcahis, sp. nov. ?£r. armatus, Burm. (head only). 



Remakks. — Of the type-species Ave only know the pygidium, but 

 the very closely allied species IT. Champernotvnei and S. hifurcatus 

 from the same locality and horizon help us to complete the above 

 definition. The regular rounded contour, semi-oval shape, well- 

 defined narrow axis, and regularly paired tubercles of the pygidium 



^ Barrois, Bull. Soc. Geol. France, ser. iii, vol. xiv, p. 687, pi. xxxiii, fig. 5, 

 1886. 



- Thomas, Zeitschr. deut. geol. Gesell., Bd. Ivii, p. 145, pi. ix, figs. 5, 6, 

 1905. 



" Koch, op. cit., p. 21, pi. i, fig. 7. 



