334 Description of new North American Trilohites. 



at all. The Chululqui is thought to be nearly equal to the Saqui ; 

 and the Chelem to bear some resemblance to the Yashqui. The 

 duration of the Sacqui, is limited at 10 or 15 years, and the biennial 

 reproduction of plants from its roots, at eight or ten young plants ; 

 while the duration and reproduction of the Yashqui is only rated 

 half as high. Here the people begin to be sensible of the value of 

 their Henequiii : and the first agricultural association ever formed in 

 Yucatan, is a company for its cultivation. I impressed them with the 

 opinion, that by it they would extract more wealth from the sandy 

 and rocky surface of this peninsula, than from all the gold and silver 

 mines of Mexico. I anti, very respectfully, 



Henry Perrine. 



Art. IX. — Descriptions of some new JVorth American Trilohites ; 

 by Jacob Green, M. D., Prof, of Chemistry in JefF. Med. Col- 

 lege. 



Caltmene? odontocephala. — Green. 



The outline of the buckler in this very remarkable species, is 

 subtriangular. The front is separated from the cheeks by a deep 

 groove on each side, its anterior edge is ornamented on each 

 side by a kind of Etruscan border, composed of alternate projec- 

 tions from the outer edge of the shell inwards, and from the inner 

 portions of the shell outwards ; the square protrusions on the one 

 side, occupying intermediate square spaces on the other. This 

 singular and beautiful structure does not surround the anterior edge 

 of the cheeks, but terminates at the separating furrow on each side. 

 At the first glance, these projections in front, give to the trilobite the 

 appearance of teeth. The surface of the front or middle portion 

 of the buckler, is marked on each side near the oculiferous tubercles, 

 with two deep pits producing several irregular pleats or folds, some- 

 what like those on the front of Calymene Blumenbachii of Brong- 

 niart. The cheeks zre triangular in shape : their lateral edges are 

 terminated by a plain raised hem, which corresponds in breadth with 

 the ornamented border of the front. The oculiferous tubercles are 

 very prominent, are almost encircled at their base by a deep groove, 

 •and have at their apices a semilunar depression. A shallow depres- 

 sion also passes from behind each of the eyes, over the surface of 

 the cheeks, nearly parallel with the furrow which separates them 

 from the front. 



