Knight — 138 — Dictionary 



Sperm-cell. — A male gamete. 



Spermateleosis. — (i) The production of mature spermatozoa 

 from spermatids, (ii) Spermatogenesis. 



Spermatid. — A haploid cell which develops directly into a 

 functional sperm without further nuclear division. See under 

 Spermatogonium. 



Spermatoblast. — A spermatid, q.v. 



Spermatocyte. — A sperm mother-cell. See under Spermato- 

 gonium. 



Spermatogenesis. — The process by which spermatozoa are 

 formed from spermatogonia. 



Spermatogonium. — A sperm mother-cell; a primordial male 

 germ cell which by mitosis produces primary spermatocytes 

 which in turn by meiosis produce secondary spermatocytes, 

 these latter divide equationally to form spermatids which de- 

 velop without further division into functional spermatozoa. 



Spermatomere. — Sperm mother-cell. 



Spermatomerite. — A chromatin particle at the anterior end 

 of a spermatozoon. 



Spermatoplasm. — The protoplasm of a spermatozoon. 



Spermatosome. — The body of a spermatozoon as distinct 

 from the chromosome content. 



Spermatosphere. — Sperm mother-cell. 



Spermatospore. — Sperm mother-cell. 



Spermatozoid. — A motile male gamete in plants. 



Spermatozoon. — Sperm, q.v. 



Spermin. — A testicular hormone affecting secondary sexual 

 characters. 



Spermiocalyptrotheca. — A cap-like structure forming the 

 apex of a mature spermatozoon. 



Spermiogenesis. — Spermatogenesis, q.v. 



Spermioteliosis. — Spermateleosis, q.v. 



Sperm-nucleus. — The nucleus of a sperm, especially before 

 fertilization after the sperm has penetrated an ovum. 



Spermogamete. — Micro-gamete. 



Sphere. — Central Body, q.v. 



Spheroplasts. — Mitochondria, q.v. 



Spindle. — The frame-work of 'fibres', or striations which is 

 formed between the two poles and the equatorial region, or 

 between the two centrioles and the equatorial region, during 

 cell division. 



Spindle Attachment. — That point of a chromatid to which 

 the spindle 'fibre' appears to be attached at metaphase and 

 anaphase and which, at anaphase, starts to move towards the 



