GLOSSAKY. 367 



Ec rooYST (Gr. eUos, outside ; kiistis, a bladder). The external investment of 

 the polypide of a PolyzoSn. 



Ectoderm (Gr. ektos, outside ; derma, skin). The external integumentary 

 layer of the Ccelenterata, 



Edentata (Lat. e, without ; dens, tooth). An order of Mammalia, in which 

 some or all of the teeth are wantin£»t Often called Briita. 



Elasmobranchii (Gr. elasma, a strap ; bragchia, gill). An order of Fishes, 

 including the Sharks and Rays. 



Elytka (Gr. ehdron, a sheath). The hard chitinous anterior pair of wings 

 in the Beetles, which form protective cases lieueath which the posterior 

 membranous wings can be folded. 



E.»fuocvsT (Gr. endon, within; kustis, a bag). The inner membrane of the 

 polypirie of a FolyzoSn. 



Endoderm (Gr. endon, within ; derma, skin). The inner integumentary layer 

 of the Coslenterata. 



Endoskeleton (Gr. endon, within ; skeletos, dry). The internal hard struc- 

 tures, such as bones, which serve for the attachment of muscles, or the 

 protection of organs, and which are not merely produced by a hardening of 

 the integument. 



Entomostraca (Gr. entoma, insects ; ostrakon, shell). Literally, " Shelled 

 Insects ; " applied to a division of the Crustacea. 



Entozoa (Gr. entos, within; zoon, animal). Animals which live parasitically 

 in the interior of other animals. 



Eqttilatebal (Lat. fnquus, equal ; latus, side). Having its sides equal. 

 Usually applied to the shells of the Brachiopoda. 



Equivalvb (Lat. cnquus, equal ; valixe, folding-doors). Applied to shells which, 

 like those of most of the Lamellibranchiata, are composed of two equal pieces 

 or valves. 



Errantia (Lat. errn, I wander). An order of Annelida, comprising forms 

 which are capable of active locomotion. 



EuRTPTERiDA (Gr. eurus, broad ; pteron, wing). A group of extinct Crus- 

 tacea. 



ExosKELETON (Gr. exo, outside ; skeletos, dry). Under this term are com- 

 prised all structures which are produced by a hardening of the integument. 



Femur, The thigh-bone, intervening between the pelvis and the bones of the 

 leg proper [tibia 3,\\6 Jibula). 



Fibula (Lat. a brooch). The outermost of the two bones of the leg in the 

 higher Vcrtebrata. 



Fission CLsA,. findo, I cleave). Multiplication by means of a process of self- 

 division. 



FissiROSTRES (Lat. fissus, cleft ; rostrum, beak). A sub-order of the Perching 

 Birds, in which the beak can be opened to a great width. 



Flagellum (Lat. a whip). Vibratile filaments, allied to cilia, but differing in 

 being much longer, and generally present only in small numbers. 



Foot. The muscular or^an developed on the under surface of the body in the 

 higher Mollusca, and subserving locomotion. 



Foot-jaws. The limbs of Crustacea, which are so modified as to subserve 

 mastication. 



Foot-tubercles. The unjointed lateral appendages of the Annelida, which 

 subserve locomotion, but are not articulated to the body. 



FORA.MINIFERA (Lat. /orame)!, an aperture ; /ei-o, I carry). An order of Pro- 

 tozoa, usually characterised by having a shell perforated by numerous holes 

 or "foramina," through which the pseudopodia are emitted. 



Fruoivorous (Lat. frux, fruit ; voro, I devour). Living upon fruits. 



Funnel.' The stomach sac of the Clenophora; the muscular tube of the 

 Cuttle-fishes by which the water filling the mantle-cavity is ejected. 



FuiicuLUM, properly Furcula (Lat. diminutive oifurca, a fork). The V-shaped 

 bone or "merry-thought " of birds, formed by the united clavicles. 



Galltnacei (Lat. rjallina, a fowl). Often applied to the entire order of the 



