SPERMATIA. 



[ 700 J 



SPERMATOZOA. 



stance through which the light reflected 

 fr.tin the mirror can be transmitted, it is 

 only necessary to place the slide carrying 

 the section or crystalline tihn or the tube 

 containing the solution in the frame adapted 

 to receive it. In either case this second 

 spectrum is seen by the eye of the observer 

 alongside of that produced by the object 

 viewed through the body of the microscope, 

 so that the two can be exactly compared. 

 Some care is requisite in the arrangement 

 and number of the prisms according to the 

 amount of dispersive power required. 



Crookes has devised a modification of this 

 apparatus, in which the prisms and slit can 

 be withdrawn and replaced without remo- 

 ving the eyepiece. 



The spectroscope is of the utmost value 

 in microscopic, as in other researches ; but 

 its study is very difficult, and we have no 

 space to enter into its minute details. 



BiBL. Sorbv, Qi(. Jn. 8c. ii. 198, Proc. 

 Boy. Soc. XV. 433, Mn. Mic. Jn. xiii. 198 

 (hluod-stains), aad Beales Hoiv, &c. 269 ; 

 Lockyer, Phil. Trans. 1874, 481, and Spec- 

 /roscoj)e ; Browning, Sj)ectroscope ; Schellen, 

 Spectroscope ; Proctor, Spectroscope ; Hug- 

 gins, Tr. Mic. Soc. 1865 ; Crookes, M. M. 

 Jn. 1869, 371 ; Suffolk, Spectr. Analys. ; 

 Vierordt, »S}^. Anal., quant., 1876 : Ward, 

 Jn. M. Soc. 1878, i. -326 {new spectroscojie) ; 

 Palmer, Mn. M. J. xvi. 277 {me<tsurement) ; 

 McMunn, Spectr. in. Med. 1881. 



SPERMATIA.— The minute corpuscles 

 supposed to represent spermatozoids in the 

 Lichens (PI. 37. tigs. .3, 15, 16) and Fungi 

 (PI. 26. figs. 2, 3, 4). 



SPERMATOZO'A of Animals. — The 

 form of the spermatozoa varies in dif- 

 ferent animals (PI. 50) ; but they usually 

 consist of a rounded or oval body or head, 

 to one end of which is appended a move- 

 able filament. This is their form in man 

 (tig. 25), and the Mammalia generally (tigs. 

 26-28) ; the former exhibit an undulating 

 membrane (Gibbes). In Birds, the body is 

 sometimes cylindrical, sometimes spiral or 

 presenting a zigzag outline (figs. 29-31). 



In Reptiles, the body is usually cylindri- 

 cal and straight ^fig. 33), sometimes spiral; 

 they are very large in Amphiuma ; but in 

 some of theni, the straight or slightly undu- 

 lating terminal filament is surrounded by a 

 spiralfibreor Undulating Membrane (fig. 17). 

 In some instances, the so-called undulating 

 membrane consists of adherent portions of 

 the formative protoi>lasm. 



In Fishes, the spermatozoa are usually 



very small, and the body rounded, al- 

 though in some the body is spiral (fig. 

 34). 



In the Invertebrata, a distinct body and 

 terminal filament are present in some ; 

 while in others each spermatozoon forms a 

 simple filament tapering at the ends (fig. 32). 

 la some instances, the body seems to exist 

 as a short cylinder or rod ; in others, the 

 spermatozoa are represented by simple cells, 

 or cells with radiating processes. 



The development of the spermatozoa is not 

 agreed upon. In the higher animals, the 

 protoplasm of the peripheral cells of the 

 seminal canals gxows inwards into finger- 

 like processes, called spermatoblasts. In 

 each of these, a nucleus is formed, constitu- 

 ting the head of the spermatozoon, the pro- 

 toplasm at the end of the process growino- 

 into the filament, so that each spermato- 

 blast produces 8 or 10 spermatozoa. Ac- 

 cording to Kolliker, thej' are developed 

 witliin the epithelial cells of the tubuli, 

 nuclei or globules arising within these, in 

 each of which a spermatozoon is found 

 coiled up (PI. 50. figs. 35, 36). In some 

 animals, the spermatozoa are formed in 

 bundles, the bodies and filaments Iving 

 parallel with and opposite each other 

 (fig. 37). _ _ . 



Most spermatozoa exhibit active move- 

 ments, produced by the action of the tila- 

 meut, whence they were formerly con- 

 sidered independent animals ; but tliese 

 movements are comparable with those of 

 the ciliated zoospores of the Algse, or the 

 cihated epithelium of animals; they are 

 increased by the addition of caustic potash. 



In some animals, tubular sheaths are 

 secreted around the masses of spermatozoa 

 while contained in the seminal apparatus, 

 and called spermatophores. These, when 

 discharged from the organ, are fixed by tlie 

 male to the posterior end of the body of the 

 female by means of a glutinous secretion. 



The spermatozoa are the essential fertili- 

 zing elements of the liquid in which they are 

 contained. 



Spermatozoa may be best examined and 

 preserved by washing them with distilled 

 water, and drying them upon a slide. 



BiBL. Kolliker, Mik. An. ii. ; id. Beitr.z. 

 Kcnntn. d. Geschlechts. d. wirb. Thiere ; 

 Czermak, Sieb. u. Kiill. Zeit. ii. ; Wagner, 

 Todd's Ct/cl. iv., art. Semen ; id. Physioloyy, 

 hy WiUis ; Leuckart, Wdyners Ilandwort. 

 d . P/iys. i\;. 819 ; Beneden, An. Conip. ; 

 Owsiannikoftj Mn. M. Jn. i. 312; Lankester, 



