116 APPENDIX. 



Phacops lafifrons is found, contains also isolated cephalic shields of this rare species. 

 Dalman, we know, has referred Stemherg's figure to \\is' CaJi/mcne speciosa {PalcBud. 76. 3), 

 which, however, according to Beyrich, is a Cheirurus, as may be seen from Hisinger's figure 

 {Leth. Suec. mippJ. Talkie XXXIX, Fig. 2), but the two anterior furrows of the glabella do 

 not traverse it entirely, and the third is bent down at each side of the centre, which is 

 not the case in TrU. Sfernhergil. It is also possible that Count Miinster's Calym. 

 Sternhergii {Beifr. iii, 37. 5, Table V, Fig. 5) and Cali/m. propinqua (ibid. 38. 6, Fig. 6), if 

 the furrows of the head do not really unite across, correspond with Phacops speciosus, whilst 

 Calgm. articidafa (ibid. 7, Fig. 7), with furrows of the head that do traverse, but which are 

 badly drawn, is more immediately referrible to Trihhites Sternhergii. Dr. Beyrich 

 enumerates all these species in his new genus Cheirurus. 



I am not yet acquainted with anything further respecting the natural position of this 

 species in the system. It I have already mentioned, and the next (see ante, p. 72). 



Triarthrus Beclii, Green, 3Ion. of Tril. 86 et seq. Monthly Americ. Journ. p. 560. 

 Harlan, Med. and Physic. Pes. 305. Brongniartia carcinoidea, Eaton, Geol. Text-Book. 

 Bronn. Leth. i, 117, Table IX, Fig. 10. Paradoxides triarthrus, Harl. 3Ied. and Physic. 

 Besearches, 401, i, Fig. 5. Parad. armatus, ibid. 402. 2, Figs. 1, 3. Milne Edw. Criist. iii, 

 345. Of these Trilobites we only know the central piece of the cephahc shield with the 

 short parabolic glabella, on which the margin of articulation is indicated by a transverse 

 furrow ; laterally, however, there are two sulcations, produced in a diagonal direction 

 towards the posterior part, which separate three nearly equal lobes. In this it entirely 

 corresponds with the head of 01. scarabaoides (see ante, p. 71). Nothing satisfactory can 

 be said or conjectured with regard to the systematic position of this species, as the maxillary 

 shields are wanting in all the specimens that have been examined, the rings of the body are 

 merely known by fragments, and the caudal shield has not yet been found. Its affinity with 

 Olen. scarahcBoides, as shown by Harlan, is very readily seen ; but the latter form also is as 

 yet not sufficiently known to enable us to draw any inference from it in regard to the 

 species at present under discussion. Harlan assumes, however, four body rings in Parad. 

 triarthrus, and a short caudal shield, which is rounded at the circumference : he represents 

 the lateral lobes of all the joints of the body as being more narrow than the axis; the 

 latter is about equal to them near the head, but the lateral lobes rapidly become shorter 

 towards the posterior part. 



In the last respect, the new genus, Bemojileurides, established by Portlock [Eep. 255, 

 PI. I Fio-s. 1-6), in some measure approaches it. It appears also to have affinity with Olenus 

 scarabesoides, and to belong to the group of Olenida. 



Agnostus s. Battus. The discovery of several complete specimens of this singular 

 genus of Trilobites has confirmed the view taken by Wahlenberg and Dalman {Palaad. 

 p. 33), viz. that both the known forms of it belong to one and the same animal in the 

 relations of cephalic and caudal shield. Dr. Beyrich has described a perfect specimen of 

 a new species from Bohemia, and proved from the analogies of the latter with previously 

 known shields, that the shields, which are usually rather larger, and furnished at the margin 

 with two points, belong to the pygidium, and that the shields undefended at the margin and 

 rather more convex, the axis being more narrow towards the front, belong to the head. 

 According to this the genus might be characterized as follows : — 



