GLOSSARY. 593 



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

 Gasteropoda ; 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 

 life. 



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



PEDICELLARI.E (Lat. pedicellus, a louse). Certain singular appendages found 

 in many Mcldnoderms, 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. pedunculus, a stem or stalk). In a restricted sense applied 

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

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



PEDUNCULATE. Possessing a peduncle. 



PELAGIC (Gr. pelayos, 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 Hydrozoa. 



PERIGASTRTC (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. 



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

 covers the shell in most of the Mollusca. 



PERIPLAST (Gr. peri; &ndplasso, I mould). The intercellular substance or 

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



PERISOME (Gr. peri ; and soma, body). The coriaceous or calcareous integu- 

 ment of the Echinodermata. 



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

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

 of toes. 



PERISTOME (Gr. peri; and stoma, 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 of a univalve shell. 



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

 the space surrounding the viscera. 



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. 



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

 Fishes comprising only the Lancelet. 



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 Belemnite. 



PHYLACTOL^EMATA (Gr. phulasso, I guard; and laima^ throat). The divison of 

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

 known as the "epistome." 



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

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



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

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

 gonoblastidia of Veleila, one of the Physophoridce. 



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

 VOL. II. 2 P 



