NO. 3 CAMBRIAN TRILOBITES l8l 



ACROCEPHALITES STENOMETOPUS (Angelin) 



Plate 24, figs. I, la-b 



Solenopleura ? stenometopa Angelin, 1851, Pal. Scand., p. 28, pi. 19, fig. 4. 

 Acrocephalites stenometopus (Angelin) Wallekius, 1895, Unders. Zonen 

 med Agnostus Icevigatus i Vestergotland, p. 53. 



The type specimen of this species, a cranidium, was sent to me 

 from the Museum at Lund. It has the front rim, the greater part 

 of the fixed cheeks, and the palpebral lobes broken off. The descrip- 

 tions and illustrations of Wallerius were evidently added to by 

 observations on other specimens. 



A photograph of the type specimen is reproduced as figure i, plate 

 24. All its characters are included in the description of the genus. 

 The frontal limb is finely shown with its large, rounded central 

 tubercle, but nothing is seen of the broad, anterior margin with a 

 deep, intramarginal furrow. These features were probably pre- 

 served on other specimens, as they are represented in the somewhat 

 diagrammatic figures of Angelin and Wallerius. 



The back side of the occipital ring is broken away in the specimen 

 illustrated bv figure i, but it may have had a spine similar in character 

 to that of ^. .^ aster (see pi. 26, figs. 9, 9a). 



The description by Wallerius is very detailed, and I can add noth- 

 ing for the use of the student except figures based on photographs of 

 the specimens of the cranidium and free cheeks. 



Formation and locality. — Middle Cambrian: (sogn) Agnostus 

 Icevigatus zone, Gudhem and Djupadal, Skaraborg, Vestergotland, 

 Sweden. 



ACROCEPHALITES TUTUS, new species 

 Plate 24, figs. 6, 6a 



The specimens of this species, like those of A. americanus pre- 

 serving thoracic segments (pi. 24, figs. 3, 3a), have had the test 

 softened and then compressed during the progress of the deposition 

 and consolidation of the mud that formed the fine argillaceous shale, 

 except that the compression and flattening were not so complete as 

 for A. americanus. This is shown by the slight convexity of the 

 species and the preservation of the granulated outer surface of the 

 test. 



Comparisons of this species with other species of the genus are 

 given under observations on the genus. 



Formation and locality. — Middle Cambrian: (141) Conasauga 

 shale; on roadside near cemetery i mile (1.6 km.) northeast of Cave 

 Spring, Floyd County, Georgia. 



