INFUSORIES. 43 



Paramoecium chrysalis, Colpoda cucullus : the last appears to occur 

 everywhere (Cosmopolite). EHRENBERG found Monas termo both 

 in stagnant water at the Red Sea, and in spring-water on Mount 

 Sinai. Colpoda cucullus is one of the most constant animals in 

 artificial Infusions, and was formerly observed by LEEUWENHOECK 

 in Infusions of pepper. 



APPENDIX 



TO THE CLASS OF INFUSORIES. 



ON (THE SO-CALLED) SEMINAL ANIMALCULES. 



(Spermatozoa.) 



VON BAER first (1827) introduced the name Spermatozoa (Nov. 

 Act. Acad. Cces. Leop. Gar. Vol. xiu) : earlier names, as animalia 

 spermatica, Cercaria seminis, &c. have merely an historical value. 



The bodies, for the most part filiform, which have been observed 

 in the fecundating fluid of animals of almost every class, have as 

 microscopic creatures been ranked with Infusories: other writers 

 class them with the Entozoa, a proceeding which can only be justi- 

 fied in a degree by the locality where they occur ; while, on the 

 other hand, it has introduced several wrong views. An independ- 

 ent organisation, in virtue of which they might be considered as 

 real animals, has not been discovered. The cause of their motion 

 is altogether enigmatical. 



LEEUWENHOECK, the discoverer of the Infusories, was the first 

 also who made observations upon these small corpuscles that in 

 appearance perform voluntary motion in male spermatic fluid. 

 Their discovery is due to a medical student, named HAM, who an- 

 nounced them to LEEUWENHOECK in August, 1677 (Phil. Trans. 

 1678, No. 142; comp. Letter 113 in the Sevende Verfolg der Brie- 

 ven, 1702, p. 65 .. ., or in the Latin edition, Continuatio Arcanorum 

 Naturce, Operum Tomo in. p. 60 sqq.). LEEUWENHOECK named 

 these bodies animals, and observed them consecutively in different 



