312 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



Gronwall, in writing of Corynexochus, stated that the genus was 

 " founded by AngeHn on two species : C. spintdosns from the Andra- 

 rum limestone, of which the head is known and the pygidium is cited 

 with ?, and C. u:, bonatus from the Orthoceras hmestone, of which 

 only the pygidium is known. The former pygidium is of a type which 

 can hardly belong to the head figured, hence it is best to follow 

 Matthew's example, and consider the head of C. spinulosus as a type 

 for the genus, which doubtless should be referred to the Olenidae, 

 and placed near Dolichometopns." ^ The second species, C. umbo- 

 natus, clearly does not belong under Corynexochus. 



Through the courtesy of Professor Gerhard Holm, of Stockholm, 

 and the kindness of Dr. Karl Gronwall, I have received wax impres- 

 sions of Angelin's type specimens of Corynexochus spinulosus on 

 which he^ based his description and illustrations. By comparison of 

 these with the cranidia of C. minor (pi. 55, figs. 6, 6a-d) it appears 

 that C. minor is a representative form of the genus. It has the same 

 type of cranidium (compare figs, i and 6b, pi. 55), and the associated 

 pygidium is similar. This indicates that the dorsal shield of C. 

 spinulosus was similar in form to that of C. minor. Corynexochus 

 senectiis (pi. 55, figs. 7, 'ja; pi. 56, figs, i, la-g) has a less expanded 

 glabella, but with that exception it is as far as known congeneric 

 with C. spinulosus. For the species having a glabella with subparallel 

 sides I have proposed the subgenus Bonnia. 



Species of Corynexochus. — The species now referred to Corynex- 

 ochus are : 



Corynexochus bornholmiensis Gronwall (pi. 55, fig. 2), Middle Cambrian. 

 ■Corynexochus brennus Walcott (pi. 57, fig. 3), Lower Cambrian. 

 Corynexochus bubaris Walcott (pi. 56, fig. 2), Lower Cambrian. 

 Corynexochus capito Walcott (pi. 57, fig. 2), Lower Cambrian. 

 Corynexochus clavatus (Walcott) (pi. 55, fig. 4), Lower Cambrian. 

 Corynexochus delagci Miquel (pi. 55, fig. 3), Middle Cambrian. 

 Corynexochus minor Walcott (pi. 55, fig. 6), Middle Cambrian. 

 Corynexochus senectus (Billings) (pi. 56, fig. i), Lower Cambrian. 

 Corynexochus spinulosus Angelin (pi. 55, fig. i), Middle Cambrian. 

 Corynexochus stephencnsis (Walcott) (pi. 55, fig. 5) Middle Cambrian. 



Generic reference of species heretofore placed under Corynexo- 

 chus and nozv referred as folloivs: 



Corynexochus romingeri Mattbew = Cor_v'!tM'Oc/zM.y stephencnsis (Walcott). 

 Corynexochus ? uinbonatus AngeVm :^ A eglina. 



^ Bornholms Paradoxideslag, Danmarks Geol. Unders^gelse, Vol. 2, No. 13, 

 1902, p. 136. 



