74 



gradually tapers towards the abdomen. The cheeks 

 form spherical triangles, and are entirely destitute of 

 oculiferous tubercles or any other markings; their 

 posterior angles project beyond the sides of the ab- 

 domen. Abdomen and tail very much compressed, 

 and composed of about ten articulations; costal arches 

 of the lateral lobes grooved^ tail attenuated. Whole 

 length half an inch. 



The Cryptolithus Tessellatus, resembles a good 

 deal the Entomostracites Granulatus of Wahlenberg, 

 and which Dr. D aim an calls Asaphus Granulatus. 

 The figure of this animal given by Brongniart, table 

 3, fig. 7, appears to be quite imperfect, and is very un- 

 like, except in the buckler, the representation of 

 Wahlenberg's fossil, given by Dalman, table 2, fig. 

 6. Though the angles of the buckler in the Asaphus 

 Granulatus are much more elongated than those of 

 the C. Tessellatus, it may perhaps be another species 

 of the same genus.* 



* The following, is Dr. Dalman's description of the Asaphus 

 Granulatus : 



A. trunco sexarticulato pygidioque laevibus, capite antice se- 

 micirculari margine granuloso, angulis posticis extensis corpore 

 longioribus. 



Animalculum singulare, inversum si inspicitur, lyram forma 

 fere similans. Caput antice semicirculare, margine distincto, 

 serie submoniliformi e granulis approximatis ornato, discus capitis 

 laevis, sed ambitus intra marginem punctis elevatis obsitus. Hie 

 ambitus, una cum margine, truncum quoque amplecti videtur, ad 

 pygidii basin usque, ubi in cornua Icevia, trunco multo longiora, 

 abit. Glabella antice fere clavaRformis, ad basin utrinque emit- 

 tens lobi rudimentum. Truncus brevis Icevis segmentis constaris 



