106 SYSTEMATIC ARRAXGEMENT 



outline and shape, and has not always a projecting axis, but this axis, when visible, is usually 

 articulated. Several subdivisions may be established in this large genus, and we may consider 

 these as so many subgenera. 



Group A. The lateral lobes not separated by any furrow from the axis of the body 

 and with no transverse furrows ; the trace of an axis wanting in the caudal shield, and the 

 indication of the glabella in the cephalic shield. The facial suture describes a circle, the 

 eyes are large, lunate, but not very prominent. — Nileus, Dalman. 



1. AsapJms [Nileus) armadillo: Scuto capitis caudfeque convexo brevi dilatato ; angulis capitis 

 -posticis obtusis: thoracis axi lobis lateralibus latiori. Loug. 1-2". 



Mef.—D^iM. Palcead. 49. 10, Table XIV, Fig. 3, a-e. Milne Edw. Crust, iii, 294. 1, 

 PI. XXXIV, Figs. 1,2. P.\ND. Beitr. 132, Tab. V, Fig. 2. L. v. Buch, Beitr. 50. 

 HisiNG. LetJi. Suae. 16, Tab. Ill, Fig. 3. Asaph, armed. Emmr. D'mcrf. 33, 15. 



Var. Minor : Nileus chiton. Pander, Beitr. 132, Tab. V, Fig. I. Milne Edw. Crust. 

 iii, 295, 2. 



Locality.— '^\^& transition limestones of Eastgothland, Husbyfjöl, and Skarpasen ; in 

 Dalecarlia, at Rathwick ; in Esthonia, at St. Petersburgh. 



Cephalic shield short, scarcely half as broad as long, uniformly convex, with rather 

 acute margins ; the eyes separated far from one another, reaching almost to the anterior and 

 posterior cephalic margins, but depressed, and with a large covering plate. 



The rings of the body short, without any division between axis and lateral lobes ; the 

 former, however, is indicated, and is almost twice as broad as the latter, which has no trans- 

 verse furrows. 



Caudal shield short, broad, curved at the basis, without a vestige of an axis. 



Remarks.^1. It is easily distinguished from Bumastes (like which, however, it has an axis not 

 separated from the lateral lobes) by the number of body rings, and not less so by the position and size 

 of the eyes, and the comparatively inferior size and less convex shape of the glabelhi. It stands, 

 however, in the same relation to the following group as Bumastes does to Iltcenus, and, as in the latter 

 case, there are analogous forms. 



2. Nil. gJomerinus, Dalm. (Arsberatt 1828. 136; Risinger, Let h. Siiec. 16). Nil. glaberrimus 

 (Milne Edw. Cr. iii, 295), with small eyes and ten body rings, may probably be identical with Bumastes 

 barriensis. Dalman's specimens were found at Husbyfjöl. 



Group B. The lateral lobes of the rings of the body separated from the axis by a 

 depressed longitudinal furrow. The diagonal furrows of these lobes seem to be always 

 present.* 



Subdivision A. — The facial suture describes an arch anteriorly, but is not angular. 



a a. The glabella and caudal axis distinctly indicated, the latter not articulated and very short (?). 

 The eyes are also flatter and depressed, lunate, and supported at the lower part by a portion 

 of the cheek-shield, upon which they are borne ; the diagonal furrows of the lateral lobes 

 appear to be slight. — Symphysurds, Goldfuss. 



* They have not been indicated in Dalman's figure in Asaph, palpebrosus and A. Imviccps, but 

 are mentioned in the description as being slight. 



