674 



GLOSSARY. 



PECTINATE (Lat. pecten, a comb). Comb-like ; applied to the gills of certain 



Gasteropods, hence called Pectinibranchiata. 



PECTORAL (Lat. pectus, chest). Connected with, or placed upon, the chest. 

 PERENNIBRANCHIATA (Lat. perennis, perpetual ; Gr. bragchia, gill). Applied 



to those Amphibia in which the gills are permanently retained throughout 



PEDAL (Lat. pes, the foot). Connected with the foot of the Mollusca. 



PEDI.CELLARIVE (Lat. pedicellus, a louse). Certain singular appendages found 

 in many Echinoderms, attached to the surface of the body, and resembling 

 a little beak or forceps supported on a stalk. 



PEDICLE (Lat. dim. of pes, the foot). A little stem. 



PEDIPALPI (Lat. pes, foot ; and palpo, I feel). An order of Arachnida com- 

 prising the Scorpions, &c. 



PEDUNCLE (Lat. pedunculns, a stem or stalk). In a restricted sense applied 

 to the muscular process by which certain Brachiopodx are attached, and to 

 the stem which bears the body (capitulum) in Barnacles. 



PEDUNCULATE, Possessing a peduncle. 



PELAGIC (pelagos, sea). Inhabiting the open ocean. 



PELVIS (Lat. for basin). Applied, from analogy, to the basal portion of the 

 cup (calyx) of Crinoids. The bony arch with which the hind-limbs are con- 

 nected in Vertebrates. 



PERGAMENTACEOUS (Lat. pergamena, parchment). Of the texture of parchment. 



PERICARDIUM (Gr. peri, around ; kardia, heart). The serous membrane in 

 which the heart is contained. 



PERIDERM (Gr. peri, around ; and derma, skin). The hard cuticular layer 

 which is developed by the coenosarc of certain of the Hydrozoi. 



PERIGASTRJG (Gr. peri, around ; and gaster, stomach). The perigastric space 

 is the cavity which surrounds the stomach and other viscera, corresponding 

 to the abdominal cavity of the higher animals. 



PERJOSTRACUHC (Gr. peri; and ostrakon, shell). The layer of epidermis which 

 covers the shell in most of the Mollusca. 



PERIPLAST (Gr> peri ; and plasso, I mould). The intercellular substance or 

 matrix in which the organised structures of a tissue are embedded. 



PERISOME (Gr. peri; and somai> body). The coriaceous or calcareous integu- 

 ment of the Echinodermata. 



PERISSODACTYLA (Gr. perissos^ uneven ; daktulos, finger). Applied to those 

 . Hoofed Quadrupeds (Ungulata) in which the feet have an uneven number 

 of toes. 



PERISTOME (Gx-. peri; andsfoma, mouth). The space which intervenes be- 

 tween the mouth and the margin of the calyx in Vorticella ; also the space 

 between the mouth and. the tentacles in a sea-anemone (Actinia) also the 

 lip or margin of the mouth oif a univalve shell. 



PERIVISCERAL (Gr. peri ; and Lat. viscera, the internal organs). Applied to 

 the space surrounding the vis<3era. 



PETALOID. Shaped like the petal of a flower. 



PHALANGES (Gr. phalanx, a row). The small bones composing the digits of 

 the higher Vertebrata. Normally each digit has three phalanges. 



PHAKYNGOBRANCHII (Gr. pharugx, pharynx ; bragchia, gill). The order of 

 Fishes comprising only the Lancelot. 



PHARYNX. The dilated commencement of the gullet. 



PHRAGMACONE (Gr. phragma, a partition ; and konos, a cone). The chambered 

 portion of the internal shell of a Bdemnite. 



PflYLACTOLjEMATA (Gr. phulasso, I guard, and laimos, throat). The division 

 of Polyzoa in which the mouth is provided with the arched valvular process 

 known as the "epistome." 



PHYLLOCYSTS (Gr. jthullon, leaf ; and kustis, a cyst). The cavities in the in- 

 terior of the " hydrophyllia " of certain of the Oceanic Hydrozoa. 



PHYLLOPODA (Gr. phullon, leaf ; and pous, foot). An order of Crustacea. 



PHYOGEMMARIA (Gr. phuo, I produce ; and Lat. gemma, bud). The small 

 gonoblastidia of Velella, one of the Pliysophoridce. 



PHYSOGRADA (Gr. phusa, bellows or air-bladder ; and Lat. gradior, I walk). 



