CHAPTER IV. 



Glossary of Pal.^oxtological Terms. 



Abei-mnt — differino- from the type. 



Aeanthopores — hollow spines occiu-rin^- between the aper- 

 tures, on the frond of a Bryozoan. 

 Adductor muscles — the closing muscles in bivalve shells. 

 Agglutinate — firmly u nited . 

 Air-chambers — the chambers below the living- chamber in 



the shells of (ephalopods. 

 Alar — pertaining to wings; the lateral primary septa of 



the Tetracoralla. 

 Alnte — having wing-like expansions. 

 Ambuhicral areas — the perforated areas in the test of an 



Echinoderm, through which the tubed feet project. 

 Anastomosing — uniting so as to form a net work. 

 Anchylosed — firmly united ; grown together. 

 Annuhis — a ring; a segment of the thorax of a Trilobite. 

 Anterior — front. 



Apophysis — a calcareous process (in interior of shells, etc.). 

 Appressed — pressed closely against. 

 Arcuate — arched ; bent like a bow. 

 Articulated — joined by interlocking processes, or by teeth 



and sockets. 

 Auricle — the ear, or anterior projection of the hinge of many 



Pelecypods. 

 A uricula te — eared . 

 Azjgous — unpaired; the azygous side of the calyx of a 



crinoid has plates differing from those of the regular 



sides. 

 Axial furrows — the furrows or depressions delimiting the 



axis in Trilobites. 

 Axis — the central longitudinal division of the body of a 



Trilobite. 



