ROLL CALL ,o, 



Mesoglea — an intermediate non-cellular layer in sponges and coeleiiterate.s. 



Metamorphosis — change in form or structure of an animal in its devclotimerif 



from embryo to adult. 

 Gradual or simple metamorphosis — young resemble adults at hatcliing cxccDt 



for absence of wmgs or color, shape, and structure of some appendages ' 

 Complete metamorphosis — young differ from adults in appearance habitat 



etc., and undergo several changes in form such as larvae, pupae, and adult. ' 

 Metathorax — posterior segment of insect's thorax. 

 Molars — grinding teeth. 



Monocotyledon — a plant that bears seeds having but one cotyledon. 

 Mother cell — primary cell before division occurs. 



Mycelium — the threadlike body of a mold, or other fungus ; made up of indi- 

 vidual threads called hyphae. 



Nematocyst — a stinging cell. 



Nervure — one of riblike structures which support membranous wing of insect. 



Notochord — a rod of cells forming the supporting axis of lower chorda tes ; found 

 in early stages of development in all vertebrates. 



Nucleus — the center of activity in the living cell. 



Nymph — larva of aquatic forms which undergo gradual or simple metamor- 

 phosis. 



Oogonia — female reproductive organs in certain Thallophytes ; the mother egg 

 cells. 



Operculum — a lid or cover. 



Oral — pertaining to the mouth ; side on which mouth lies. 

 Ovary — (Bot.) the base of a pistil, containing the ovules. 

 (Zool.) — the egg-containing organ. 



Ovule — egglike cell of a plant. 



Papillae — any small nipplelike projections or parts. 



Parapodia — paired appendages used in locomotion, attached to body segments 



of some marine worms. 

 Parasites — animals or plants which live at the expense of other organisms. 

 Parietal eye — rudimentary eye ari-sing as an evagination on the median dorsiil 



surface of the brain. 

 Parthenogenesis — reproduction without fertilization by a male element. 

 Pedicellariae — minute pincerlike structures studding the surface of some of the 



echinoderms. 

 Pentamerous — made up of five parts. 



Peritoneum — membrane which lines the abdominal walls and invests the con- 

 tained viscera. 

 Phylogenesis — history of evolution of species. 

 Placenta — organ through which the mammalian embryo is nourished by the 



mother. 

 Placoid scales — embedded scales and dermal teeth of elasmobranchs. 

 Plantigrade — walking with sole of foot touching the ground. 

 Plasmodium — a single mass of living material which contains many nuclei. 

 Plastid — small bodies of .specialized protoplasm lying in cytoplasm of some 



cells — especially plants and certain protozoans. 

 Plastron — ventral bony shield of tortoises and turtles. 



Poison gland — gland which secretes poison, used for protection or food-getting. 

 Pollen tube — a tubular process developed from pollen grains after attachnu-nt 



to stigma. 



