OF THE SPECIES. 109 



6. Asaphus raniceps : Scuto capitis parabolico, acuto, angulis posticis subacutis ; rLaclii cauda; 

 subarticulata. Long. 3-4". 



Be/.—BAhM. Palcead. Table III, Fig. 4. Crypton. Weissii, Eichw. Ohscrv. AG, § 51. 

 Table II, Fig. 2, a, b. Milne Edw. Crunt. iii, 304. 13. Razoumowsky, An. des 

 Sc. Kaf. viii, PL XXVIII, Fig. 1. Pander, Beifr. Table IV, C, Fig. 3 Table VI, 

 Fig. XXIII. Table VII, Figs. 1, 5, 6. Table VIII, Fig. 7. 



Occurs in company with A. e.vjjansus. This species has been taken for a variety of 

 A. expansus by many authors, but is certainly a different species. 



The whole cephalic shield, and especially the glabella, is much more depressed, the 

 external margin produced and acutely angular, the anterior angle pointed. The eyes at the 

 same time are always higher, the rings of the body comparatively flatter, the caudal shield 

 parabolic, certainly not acutely angular at the posterior part, but much more lengthened ; 

 it is also more flatly arched, and the a.xis has only very slight indications of rings. 

 Even if all these diS"erences were to be considered as merely relative, and, therefore, as 

 mere characters of variation, yet the remarkably acute, angular, facial suture, which is 

 curved by the side of the angle, would constitute a good positive distinction. 



The eyes are also situated rather more close to each other. 



7. Asaphus extemiatus : Scuto capitis parabolico, acuto, angulis posticis in cornua productis ; rbachi 

 caiidse subarticulata. Long. 4-10". 



Bef. — Entom. extemiatus, Wahlenb. N. Act. Ups. viii, 295, Table VII, Fig. 4. 



Asaph, exten. Dalm. 43. 3, Table II, Fig. 3. Hising. Leth. Suec. 13, Table IL Fig. 3. 

 Isoteles. exten. Milne Edw. Cr. iii, 301. 8. 



Individiia maxima :— Asaph, grandis, Sars' Isis, 1835, 338, Table IX, Fig. 6, a,b. 

 Milne Edw. Crust m., 311. 9. 



Found in a gray limestone of Eastgothland, at Husbyfjol and Hela ; in the black 

 limestone at Aggersbakken, near Christiania. 



The peculiar lengthened form of the cephalic shield, its greatly produced posterior 

 angles, and the long, parabolic, but not actually pointed caudal shield, conspicuously 

 distinguish this beautiful and rare species. The arch of the glabella is moderate, the 

 furrowing between the eyes not very strong, and the thickened margin of articulation 

 slightly developed. The rings of the axis are much more narrow than the lateral lobes, 

 and very short, compared with the size of the caudal shield. The latter has a long parabolic 

 form, and a slightly elevated axis, on which the rings are indicated in the horny shell as 

 in Asaph, tyrannus, by little elevated transverse ridges, similar fine, radiating, minute ridges 

 also appear at the sides. This I could perfectly distinguish in Sars' large individual, of 

 which I found a plaster cast in the Berlin Museum. The latter appears to me to be difl'erent 

 only in size ; the specimens of Dalman and Wahlenberg appear to have lost their shell, 

 or at least the sculptured surface, but this, according to all analogy, would be less consider- 

 able in small than in large individuals. 



