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APPENDIX.

Phacops latifrons is found, contains also isolated cephalic shields of this rare species.Dalman, we know, has referred Sternberg’s figure to his Calymene speciosa (Palcead. 76. 3),which, however, according to Beyrich, is a Cheirurus, as may be seen from Hisinger ’s figure(Leth. Suec. suppl. Table XXXIX, Fig. 2), but the two anterior furrows of the glabella donot traverse it entirely, and the third is bent down at each side of the centre, which isnot the case in Tril. Sternberyii. It is also possible that Count Munster’s Cuhjm.Sternbergii ( Beitr. iii, 37. 5, Table V, Fig. 5) and Calym. propinqua (ibid. 38. 6, Fig. 6), ifthe furrows of the head do not really unite across, correspond with Phacops speciosus, whilstCalym. articulata (ibid. 7, Fig. 7), with furrows of the head that do traverse, but which arebadly drawn, is more immediately referrible to Trilobites Sternberyii. Dr. Beyrichenumerates all these species in his new genus Cheirurus.

I am not yet acquainted with anything further respecting the natural position of thisspecies in the system. It I have already mentioned, and the next (see ante, p. 72).

Triarthrus Pechii, Green, Mon. of Tril. 86 et seq. Monthly Anieric. Journ. p. 560.Harlan, Med. and Physic. Res. 305. Brongniartia carcinoidea, Eaton, Geol. Text-Book .Bronn. Leth. i, 117, Table IX, Fig. 10. Paradoxides triarthrus, Harl. Med. and Physic .Researches, 401, i, Fig. 5. Farad, armatus, ibid. 402. 2, Figs. 1, 3. Milne Edw. Crust, iii,345. Of these Trilobites we only know the central piece of the cephalic shield with theshort parabolic glabella, on which the margin of articulation is indicated by a transversefurrow; laterally, however, there are two sulcations, produced in a diagonal directiontowards the posterior part, which separate three nearly equal lobes. In this it entirelycorresponds with the head of 01. scarabceoidcs (see ante, p. 71). Nothing satisfactory canbe said or conjectured with regard to the systematic position of this species, as the maxillaryshields are wanting in all the specimens that have been examined, the rings of the body aremerely known by fragments, and the caudal shield has not yet been found. Its affinity withOlen. scarabceoides, as shown by Harlan, is very readily seen; but the latter form also is asyet not sufficiently known to enable us to draw any inference from it in regard to thespecies 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 representsthe lateral lobes of all the joints of the body as being more narrow than the axis; thelatter is about equal to them near the head, but the lateral lobes rapidly become shortertowards the posterior part.

In the last respect, the new genus, Reniopleurides, established by Portlock (Rep. 255,PI. I, Figs. 1-6), in some measure approaches it. It appears also to have affinity with Olenusscarabceoides, and to belong to the group of Olenidce.

Agnostus s. Battus. The discovery of several complete specimens of this singulargenus of Trilobites has confirmed the view taken by Wahlenberg and Dalman (.Palcead.p. 33), viz. that both the known forms of it belong to one and the same animal in therelations of cephalic and caudal shield. Dr. Beyrich has described a perfect specimen ofa new species from Bohemia , and proved from the analogies of the latter with previouslyknown shields, that the shields, which are usually rather larger, and furnished at the marginwith two points, belong to the pygidium, and that the shields undefended at the margin andrather more convex, the axis being more narrow towards the front, belong to the head.According to this the genus might be characterized as follows :—