114 APPENDIX. 



contour of which it harmonizes best, if we might venture to assume that the two portions 

 have been incorrectly represented in the drawing. 



CuJfjmene variolaris, Brongn. Crust, fosn. 14. 3, PI. I, Fig. 3, a, c, Parkins. Organ, rem. iii, 

 PI. XVII, Fig. IG. Dalm. Pß/^«f/. 61. 1. Buckl. Brid(/. Tr. Pl.XLVI, Fig. 6. Münster, 

 Bdtr. iii, 34. 1, Table V, Fig. 1. Murchis. Sil. Sj/stem, 655, Plate XIV, Fig. 1. Milne 

 Edw. Cr. iii, 326. Trilob. variolar. Schloth. Nachtr. ii, 34. 3. Phacops variol. Emmr. 

 Dissert. 20. 4. This species has already been mentioned (see ante, p. 83) as a form with 

 ■which I am unacquainted. It has a semicircular cephalic shield with a very convex 

 glabella which is undivided and broader at the anterior part, and with terminating angles 

 which are suddenly produced into long points. The eyes are situated in the centre beside the 

 glabella, on the surface of the cheek-shields, nearly as in Cahjmeiie Blunienhachii, presenting 

 also the form of the latter. The body becomes more narrow towards the posterior part, and 

 has distinctly thirteen rings in Murchison's figure, but only eleven in Brongniart's. The 

 caudal axis, according to the reckoning of the latter, consists of twelve rings, and there are 

 nine lateral ribs on the shield ; in Murchison's figure I can only count seven lateral ribs, and 

 from eight to nine joints in the axis. In addition to this, the whole upper surface of the 

 body is covered with large, strong protuberances, which are almost entirely wanting on the 

 body in Murchison's figure, but are represented in several rows upon the caudal axis, whilst 

 Brongniart's figure also shows strong protuberances on the body, and only one central row 

 on the caudal axis. Buckland's figure agrees with Brongniart's, and is probably copied 

 from it. The species is found in the middle Silurian rocks of England, and also in the 

 Fiehtelgebirge, on the authority of Count v. Minister. The Count's figure agrees better with 

 Murchison's than with Brongniart's ; the long pointed angles of the cephalic shield are 

 wanting in it, as in the one figured in the Silurian System.* 



Judging from these statements, I am almost inclined to consider the different forms as 

 being specifically different, and to call Murchison's species a true Calymene, Brongniart's 

 and Parkinson's a Phacops. Boeck's assertion, however, that Calymene variolaris forms a 

 distinct genus, to which the Cal. jmnctata, AuCT. also belongs, is opposed to this assumption. 

 (See Keilhaus, Gaea Norv. I. Trilob. No. 13.) The following authors treat of the last- 

 named species. 



Tril. punctatus, Brunn, Kjöhenh. Selkk. Skrivt. mje. Saml. i, 394. 5. Schloth. Nachtr. 

 ii,37. 23. Entomostr.punct. Wahlenb. N. J. Ups. viii, 32. 7. Linn^eus, Act. Beg. ac. Holm. 

 1759. 22. 24, Table I, Fig. 2. Lehmann, Nov. Comm. Petropol. x, Table XII, Fig. 10. 

 Beckm. Nov. Comm. Göthing. iii, 102. Wilck, Strals. Magaz. iv, St. Table III, Fig. 12. 

 Cahjm.punct. Brongn. Cr.foss. 36. 'Dk.-LU.Palaiad. 64. 12. Murchis. /. c. ii, 661, PI. XXIII. 

 Fig. 8. Milne Edw. Cr. iii, 327. 



All of them merely describe caudal shields, with the exception of Wahlenberg, who 

 also figures the central piece of the cephalic shield, which bears distinct marks of being a 

 Calymene, especially in the thickened anterior margin of the head, and a peculiar structure 

 of the lobes of the glabella, which reminds us of Cal. Blumenhachii. But I doubt whether 



* Cal. intermedia, Münster (35. 2, Table V, Pig. 2), is said to Lave foiu- sulcations on each side 

 uf the glabella, but resembles C. variolaris so perfectly in other respects, that I must yet doubt whether 

 it forms a distinct species. 



