Glossary 



383 



hormone (which see) for theiu, 

 and has revealed their great im- 

 portance not only for physiology, 

 hut for philosophical Inology. 



Involution. Literally inrolling, or 

 inwrapping. In descriptive hiol- 

 ogy used to signify the return of 

 an organ to its original or nor- 

 mal condition after some violent 

 or pronounced deformation of it. 

 Sometimes, but apparently un- 

 justifiably, used as a synonym of 

 degeneration. Since the doctrine 

 of evolution has become prom- 

 inent in biology, a process the 

 oi)])osite of evolution has l)een 

 thought by some to be necessary, 

 and to this involution has been 

 applied. 



Jei.ly-fish. In the interest of dis- 

 criminative knowledge, the habit, 

 rather common among people 

 who have the opportunity to see 

 the transparent, somewhat gela- 

 tinous-appearing animals of the 

 ocean, of calling them all "jell}'- 

 fishes" should be abandoned. The 

 name should be restricted to the 

 regularly disc- or dome-shaped, 

 tentaculated animals belonging 

 to the coelenterate phylum, thus 

 enlarging the bounds of defmite, 

 popular zoological information, 

 by recognizing that marine ani- 

 mals of several large and very 

 distinct classes have this general 

 consistency and appearance. 



Karyoplas^i. a cytological name 

 referring to the substance or 

 plasm distinctive of the cell-nu- 

 cleus. 



Karyosome. a small, discrete, 

 rather constant body which 

 stains readily, contained in the 

 cell-nucleus; frequently synony- 

 mous with nucleolus. 



Katabolism. The down-breaking, 

 or descensive phase of metabol- 

 ism; the opposite of amibolism 

 (which see). 



Ktneto-nuci.eus. One of the nu- 

 clei in the two-nuclear protozoa 



supposed to be concerned in 

 some special way with the move- 

 ment of the flagclla or cilia of 

 tliese animals. 



l.A.-\iKi,r.AE, singular lavtella. A 

 term much used in anatomy to 

 designate the thin plates, .scales, 

 etc., that are so nuiiu-rous and 

 varied in form and size in nearlv 

 all organisms. 



Larva. Properly apj)Iied only to 

 stages in the lives of iiulividii.il 

 animals which ])ass into succeed- 

 ing stages through ;i deep-sealed 

 nu'tam()rj)hosis, as for example 

 the grub or maggot of a fly, and 

 its transformation into the adult. 

 Larval stages aiul ])rofoiin(l 

 metamorphoses are very con)tnon 

 and widespread in the animal 

 kingdom. 



LiMULus. The technical genus 

 name for the horse-shoe crab, an 

 animal of special interest to gen- 

 eral zoology in several ways. 



Macronuci.evs. In the infusoria, a 

 group of jirotozoans, there is one 

 large nucleus and one or several 

 nnich smaller nuclei. 'I'he first is 

 called, from its relatively large 

 size, the ;/K»r/o-nucleus; the 

 others m/r-ro-iuu-Iei. From th<- 

 behavior of the two kiiuls of nu- 

 clei at conjugation and (livi>ioM, 

 the micronuclei are known to be 

 intimately comiected with these 

 processes, while the macromicleus 

 seems to be more coneeriu-tl with 

 the nutritive functions of the 

 arn'nial. 



IMANiiuur.-M. In n)orj)hoIogv n 

 part or organ which resembles a 

 handle; specially the clajipcr- 

 like, or handle-like portion of a 

 medusa which is found within 

 the "bell." The animal's mouth 

 is at the erul of i\\e manubrium, 

 aiul most of its digestive cavity 

 within the stalk of the maiui- 

 iirium. 



•ALvniix. In biology the ground 

 substanie in which cells arc em- 



