SYNOPSIS OF GENERA. 
XXXI 
1883. Bahnanites, Novak. Zur Kennt. liohm. Trilob. 
1884. Balmanites, Novak. Studien an Hypostomen, ii. 
1884. Bahnanites, Walcott. Palffionlol. Eureka Dist. 
1885. Bahnanites, Clarke. Geol. Succesion in Ontaiio Co. 
1885. Bahnanites, CEhlert. Bull, de la Soc. d’Etudes Scientif. d. Anger.'s. 
1886. Bahnanites, Barrois. Bull, de la Soc. geol. de France. 
1887. Bahnanites, Fcerste. Bull Denison. Univ. 
The species of the genus Balmanites frequently exhibit a tendency to varia¬ 
tion in many of their more important features. This variability may be either 
in the relative development of the lateral glabellar furrows, the coalescence of 
the glabellar lobes, or in the ornamentation of the margins of the cephalon and 
pygidium; the features of the glabella are of more distinctive importance, 
the ornamental characters undoubtedly being of a somewhat more fugitive 
value. By the unequal development and suppression of the glabellar lobes 
and furrows, there is an evident transition from the typical Balmanites to the 
typical Phacops. Again, the gradual coalescence of the lateral glabellar lobes 
produces forms following the type of the genus Chastnops, in which the first two 
pairs are united, and of the genus Manorakos, in which the three lobes of each 
side are coalesced. The ornamental features are of importance in the establish¬ 
ment of subordinate groups of a provisional character. It is here proposed to 
group under the term Hausmannia the typical and unvaried forms of Balmanites 
which follow the type of B. caudatus, (Briinnich) Emmrich, and B. Hausmanni, 
Brongniart. 
Sub-genus HAUSMANNIA, n. s.-g. 
Diagnosis. Body elongate-ovate, depressed- 
convex. Cephalon lunate; genal angles produced 
into spines; glabella scarcely prominent; frontal 
lobe transverse or sub-rhomboidal; all the lateral 
lobes well developed. Thorax composed of eleven 
segments; pleurae beveled, the posterior segments 
often produced. Pygidium large, bearing more 
than eleven annulations; margin entire, often pro¬ 
duced into a caudal spine. 
The Devonian species, which are referred to 
this group, are to some extent imperfectly known, and it may eventually 
