the cabinet of Mrs. Downing of the Priory near Dudley, 

 enables me to say that it has 11 thorax segments." 



Emmrich, in the De Trilobitis Dissertatio, etc., 1839, 

 on p. 20, describes, under Phacops variolaris, Park., the 

 Crypt, punctatus, as follows : " Head tuberculated ; the 

 posterior angles are produced into short horns ; glabella 

 convex : the thorax posteriorly diminishes ; pygidium 

 pointed." 



In 1840, Eichwald, in his Silurian System of Esthland, 

 on p. 71, gave to his former generic name, Cryptonymua 

 another signification, and proposed this genus for such 

 typical forms as Calymene punctata and C. variolaris, 

 in part, with Cryp. Wcerthii and C. parallehis. In thus 

 abandoning his claims of priority for his genus, Crypto- 

 nymus, of 1825, over Dalman's genus, IlloBnus, of 1826, 

 the author substituted for his genus a generic name, 

 which had been used for an entirely different set of 

 fossils, and only pointed out his generic type, without 

 giving a defined description of the genus. To us it ap- 

 pears that he has clearly indicated the group, and given 

 a definite exposition of its essential characters in assign- 

 ing Calymene punctata, Dal., for the type. Eichwald 

 says, in his Die Urwelt Russlands, p. 22 : "I found also 

 in Odinsholm fragments of other species, viz : Calymene 

 variolaris, Brong., which belongs to the genus Orypto- 

 nymus. * * * j discovered near Reval an interest- 

 ing small species of Cryptonymus, which has a pygidium 

 similar to Calymene punctata, Dalman," 



Munster, in his Beit, zur Petrefactenkunde, vol. iii, p. 

 34, pi. V, fig. 1, describes and figures Crypt, variolaris. 



In 1843, Burmeister, in his work on the Organization 



would restrict the name to the latter ; but custom and the opinion, of natural- 

 ■<i8ts in general would point in doutful cases like this to the first as the typical 

 ipecies, and we should then have to apply Zethus to all we now call C%cir>i- 

 rus ; more especially as it was only the entire body of Cheirurus that 

 Pander knew. (Fide Salter. Decade vii, part ii, p. 9.) 



