672 GLOSSARY. 



DiccELOUS. (Gr. dis ; koilos, a cavity.) A heart with two cavities. 



DiDACTYLE. (Gr. dis; and dactulos, a finger.) A limb terminated by two fingers. 



Digitate. (Lat. digitus, a finger.) When a part supports processes like fingers. 



Dimidiate. (Lat. dimidium, half.) Divided into two halves. 



])i<ECious. (Gr. dis, twice, and oikos, a house.) The species which consist of 



male and female individuals. 

 Dimtary. (Gr. dis; muon, a muscle.) A bivalve whose shell is closed by two 



muscles.' 

 DiPTERA. (Gr. dis ; pteron, a wing.) The insects which have two wings. 

 Discoid. (Lat. disctis, a quoit.) Quoit-shaped. 



Distoma. (Gr. dis ; stoma, mouth.) The intestinal worms with two pores. 

 Diverticttlum. (From the Latin for a bye-road.) Applied to a bhnd tube 



branching out from the course of a longer one. 

 Dorsad. (Lat. dorsum, the back.) Towards the back. 

 DoKSiBRANCHiATE. (Lat. dorsum ; and bragchia, gills.) The Mollusca with gills 



attached to the back. 

 DoRSO-iNTESTiNAL. A part which is on the dorsal aspect of the intestine. 

 Ductus. A duct or tube which conveys away the secretion of a gland. 

 Duodenum. The first portion of the small intestine, which, in the human subject, 



equals the breadth of twelve fingers. 



EcDYSis. (From the Greek, signifying the act of stripping.) Moulting of the 

 skin. 



Echinoderms. (Gr. echinos, a hedgehog ; derma, skin.) The class of radiated 

 animals, most of which have spiny skins. 



Edentulous. From the Latin word for toothless. 



Edriophthalma. (Gr. edraios, sitting or sessile ; and ophthalmos, an eye.) The 

 Crustacea with sessile eyes. 



Elytra. (Gr. elntron, a sheath.) The wing sheaths formed by the modified an- 

 terior pair of wings of beetles. 



Emarginate. (Lat. emargino, to remove an edge.) When an edge or margin 

 has, as it were, a part bitten out. 



Emunctories. (Lat. emungo, to wipe the nose.) Parts which carry out of the 

 body useless or noxious particles. 



En ALIOS AUR. (Gr. enalios, marine ; sauros, a lizard.) An extinct order of marine 

 gigantic reptiles allied to crocodiles and fishes. 



Encepiiala. (Gr. en, in ; kephale, head.) The molluscous animals which have a 

 distinct head. 



Entomology. (Gr. entoma, insects ; logos, a discourse.) The department of Na- 

 tural Histoiy which treats of insects. 



Entomostraca. (Gr. entoma, insects; ostracon, a shell.) The order of small 

 Crustaceans, many of which are enclosed in an integument, like a bivalve shell. 



Entozoa. (Gr. entos, within ;, zoon, animal.) The animals which exist within 

 other animals. 



Eocene. (Gr. eos, the dawn ; kainos, recent.) The tertiary period, in which fhe 

 extremely small proportion of living species indicates the first commencement or 

 dawn of the existing state of animate creation. 



Epidermal. (Gr. epidermis, the cuticle.) Belonging to the cuticle or scarf-skin. 



Epimeral. (Gr. epi, upon; meron, a limb.) The part of the segment of an ar- 

 ticulate animal which is above the joint of the limb. 



Epiploon. (From the Greek.) It is the fatty membrane which covers or occupies 

 the interspaces of the entrails in tlie abdomen. 



Episternal. (Gr. epi, upon ; sternon, the breast-bone.) The piece of the segment 

 of an articulate animal which is immediately above the middle inferior piece or 

 sternum. ^ 



Epithelium. The thin membrane which covers the mucous membranes : it is 

 analogous to the epiderm of the skin. 



Epizoa. (Gr. epi, upon ; zoon, animal.) The class of low organised parasitic 

 Crustaceans which live upon other animals. 



Errantes. (Lat. erro, I wander.) An order of the class Annelida, remarkable 

 for their locomotive powers. 



Excito-motory. Tlie function of the "nci-vous system by which an imp'-cssion is 



