106 GLOSSARY. 



Phrag'macone (Gt.pAragma, a partition ; konos, a cone). The 

 conical part of the internal shell of a belemnite, which is 

 divided into chambers by partitions. 



Phre'nic (Gr. phren, the diaphragm). Relating to the dia- 

 phragm, as the phrenic nerve, which is supplied by the 

 spinal cord to the diaphragm. 



Phylactolae'mata (Gi.pJmlakteous, guarded; laimos, the throat). 

 The division of the Polyzoa, the members of which 

 possess an epistoma and a horseshoe-shaped lophophore. 



Phylo'geny (Gr. phulon, tribe, species; genos, lineage). A 

 branch of Biology which attempts to gather the ancestral 

 history of an animal from its development 



Physema'ria (Gr. phusema, a bubble ; L. mare, the sea). A 

 group of low marine Metazoa. 



Physiology (Gr. phusis, nature ; logos, a discourse). The 

 science which treats of the various operations which take- 

 place in living beings, and which constitute life. 



Physo'poda (Gr. phusa, wind ; pous, podos, a foot). A group of 

 small winged insects which live mostly in plants. 



Physo'tomi (Gr. phusiao, I inflate). A group of Teleostean 

 fishes in which an air-bladder is nearly always present. 



PhytS'phaga (Gr. phuton, a plant ; phago, I eat). A division 

 of the Edentata which comprises all the vegetable-feeding 

 forms. 



Pi'a ma'ter (L. tender mother). The delicate, highly vascular 

 membrane which forms the innermost of the three cover- 

 ings of the brain and spinal cord. 



Pfll'dium (Gr. pllidion, a small felt hat). A helmet-shaped 

 body in which the larva of the Nemertidae is developed, 

 and which is subsequently cast off. 



Pine'al gland (L. ptnea, a pine). A glandular body connected 

 with the roof of the third ventricle of the brain, the 

 function of which is at present unknown. 



Pin'na (L. a fin or pinion). The expanded portion of the 

 external ear; also the primary divisions of a fern frond. 



Pinnipe'dia (L. pinna, a fin ; pes, pedis, a foot). A division of 

 the Carnivora which comprises the seals and walruses. 



Pin'nule (L. pinnula, a little feather). The small lobes or, 

 leaflets of the frond of a fern, or of the leaf of any other 

 plant similarly divided. Also each radiating process of 

 the arms of a Crinoid. 



Pis'ces (L. piscu, a fish). The class of the Vertebrata which 

 includes the fishes. 



