Enderon

(Gr. en, in; deros, skin). The inner plane of growth of the outer integumentary layer (viz., the ectoderm or epidermis).

Endocyst

(Gr. endon, within; kustis, a bag). The inner membrane or integumentary layer of a Polyzoon. In Cristatella, where there is no " ectocyst," the endocyst constitutes the entire integument.

Endoderm

(Gr. endon ; and derma, skin). The inner integumentary layer of the Ccelenterata.

Endopodite

(Gr. endon; and pous, foot). The inner of the two secondary joints into whicn the typical limb of a Crustacean is divided.

Endosarc

(Gr. endon; and sarx, flesh). The inner molecular layer of sarcode in the Amoeba, and other allied Rhizopods.

Endoskeleton

(Gr. endon ; and skeletos, dry). The internal hard structures, such as "bones, which serve for the attachment of muscles, or the protection of organs, and which are not a mere hardening of the integument.

Ensiform

(Lat. ensis, a sword ; forma, shape). Sword-shaped.

Entomophaga

(Gr. entoma, insects; phago, I eat). A section of the Marsupialia.

Entomostraca

(Gr. entoma, insects; ostrakon, a shell). Literally, shelled insects - applied to a division of Crustacea.

Entozoa

(Gr. entos, within; zoon, animal). Animals which are parasitic in the interior of other animals.

Eocene

(Gr. eos, dawn; kainos, new or recent). The lowest division of the Tertiary rocks, in which species of existing shells are to a small extent represented.

Ephippium

(Gr. ephippion; Lat. ephippium, saddle). A receptacle on the back of the Daphnia, in which the winter eggs are deposited.

Epidermis

(Gr. epi, upon; derma, the true skin). The outer non-vascular layer of the skin, often called the scarf-skin or cuticle.

Epimera

(Gr. epi, upon; meron, thigh). The lateral pieces of the dorsal arc of the somite of a Crustacean.

Epipodia

(Gr. epi, upon; pous, the foot). Muscular lobes developed from the lateral and upper surfaces of the "foot" of some Molluscs.

Epipodite

(Gr. epi, upon; pous, foot). A process developed upon the basal joint, or " protopodite," of some of the limbs of certain Crustacea.

Episterna

(Gr. epi, upon; sternon, the breast-bone). The lateral pieces of the inferior or ventral arc of the somite of a Crustacean.

Epistome

(Gr. epi ; and stoma, mouth). A valve-like organ which arches over the mouth in certain of the Polyzoa.

Epitheca

(Gr. epi; and theke, a sheath). A continuous layer surrounding the thecae in some Corals externally.

Epizoa

(Gr. epi, upon; zoon, animal). Animals which are parasitic upon other animals. In a restricted sense, a division of Crustacea which are parasitic upon fishes.

Equilateral

(Lat. oequus, equal; latus, side). Having its sides equal. Usually applied to the shells of the Brachiopoda. "When applied to the spiral shells of the Foraminifera, it means that all the convolutions of the shell lie in the same plane.