GLOSSARY OF SCIENTIFIC TERMS. 



Extracted principally from Professor Owen's learned work entitled, " Lectures on tha 

 Comparative Anatomy and Physiology of the Invertebrate Animals." 



Ambulacra (L. ambulacrum, an avenue, 

 or place for walking). The perforated 

 series of plates in the shell of the Sea- 

 star, or Sea-urchin, through which the 

 sucking-feet are protruded. 



Acalepha (Gr. akalephe, a nettle). The 

 class of radiated animals with soft 

 skins which have the power of stinging 

 like a nettle. Commonly called Sea- 

 nettles or Jelly-fish. 



Actinse Gr. aktin, a ray). The genus of 

 Polypes which have many arms radiat- 

 ing from around the mouth. 



Alternate generation. That modifica- 

 tion of gen er ation in which the y oun g do 

 not resemble the parent, but the grand- 

 parent ; so that the successive series of 

 individuals seem to represent two spe- 

 cies, alternately reproduced, in which 

 also parthenogenesis alternates with the 

 ordinary engendering by impregnation. 



Algae (sea-weeds). A large class of 

 cryptogamic plants inhabiting salt and 

 fresh water. 



Anomoura (Gr. anomos, irregular, and 

 our a, a tail). A section of crustaceous 

 animals distinguished like the Hermit 

 crabs, by the irregular form of the 

 tails. 



Annelid. The Anglicised singular of 

 annelleta. 



Adductor muscles, are those which hold 



together the shell of a bivalve, such as 



the Oyster, Mussel, <fec. 

 Animalcules. Those extremely small 



animals which are invisible to the 



naked eye. 

 Antenna (from the Latin for yard-arm). 



Applied to the jointed feelers or horns 



upon the head of insects and crus- 



tacea. 



Balanoids (Gr. lalanos, an acorn). A 

 family of Sessile cirripeds, the shells of 

 which are commonly called Acorn- 

 shells. 



Bivalve. When a shell consists of two 

 parts, closing like a double door. The 

 mollusca so protected are commonly 

 called bivalves, as the Mussel. 



Brachyura (Gr. brachus, short; oura, 

 tail). The tribe of Crustacea with short 

 tails, as the Crabs. 



Branchiae. The gills or respiratory 

 organs which extract the oxygen from 

 air contained in water, as in fishes and 

 other aquatic animals. 



Buccal (L. bucca, mouth). Belonging to 

 the mouth. 



Byssus (Gr. byssos, fine flax). A term 

 applied to the silken filaments or 

 ' beard ' of the Mussel and Pinna. 



