Index to N. P. Angelin's Palseontologia Scandinavian, with notes 27 



Note 



This species ought to be called Illcenus centaurus ANGELIN (not DALMAN). On describing this species 

 ANGELIN thought proper to refer to it some free cheeks produced in great spines, which DALMAN 

 (Om Palseaderna. Kgl. Vet.-Akad. Handl. 1826, p. 261) had before mentioned under the provisional 

 name Asaphus (Illcmus) centaurus. He therefore added to his figure great genal spines and cited 

 DALMAN as the auctor of the species in question. ANGELIN'S figure is rather rough and his descrip- 

 tion not very characteristic, but afterwards STEINHARDT (1874, p. 47), who had to his disposal :i 

 specimen determined by ANGELIN, gave a detailed description of the species and furnished good 

 natural reproductions of it (without free checks). HOLM (1883, p. 90), after examining the free 

 cheeks mentioned by DALMAN, which have proved to belong to a Megalaspis, probably identical 

 with M. latilimbata ANG., thought proper for the free cheeks mentioned to keep the name M. 

 centaurus DALM. sp. and also to give a new name Illcenus Chiron HOLM to the Mlcenus-species 

 referred to by ANGELIN. 



HOLM does not seem to have duly taken into consideration the fact that DALMAN'S Asaphus 

 (Illcenus) centaurus was based not only on the free cheeks but also on fragments of a cranidium, which 

 may possibly suggest that DALMAN based his I. centaurus on fragments, part of which belonged 

 to some species of Megalaspis, others again to a veritable Illcenus. As it might be difficult to 

 decide what the Illcenus centaurus of DALMAN has really been, all the more as it may be scarcely 

 possible to distinguish Megalaspis-spccies of the latilimbata-type only by means of the free cheeks, 

 and on the other hand ANGELIN'S Illcenus centaurus (apart from the free cheeks) has never given 

 occasion to any doubt as to which species is intended, it seems as REMELE (1883, p. 41, note 4) 

 and other authors have before pointed out not very appropriate to introduce a new name for 

 the latter species. 



SCHMIDT, who accepted his collaborator HOLM'S denomination for Illcenus centaurus, considered 

 the free cheeks mentioned by DALMAN to be identical with those of Megalaspis grandis SARS sp. 

 and proposed to exchange this name into Megalaspis centaurus DALMAN sp. After what has been 

 said above, this, however, may hardly be considered appropriate. 



Compare HOLM 1883, p. 99. As to the hypostoma compare LINDSTEOM 1901, pi. 3, fig. 55. 



See Liostracus muticus. 



See the note to Acontheus. 



By LINNARSSON 1879, p. 17, referred to the genus Conocoryphe. The >tail>, by ANGELIN ascribed to this 



species, is according to GRONWALL 1902, p. 97, really a headshield belonging to C. breviceps. 

 See the note to Cryptonymus. 



See Cryptonymus. 



