. 
1903.] PHILLIPS—A REVIEW OF PARTHENOGENESIS. 291 
2. Complete—to adult condition. 
(a) Occasional—exceptional—Tychoparthenogenesis (Henne- 
guy). 
€.g., Bombyx mort. 
(2) Normal—Isoparthenogenesis (Hatschek). 
(1) No Alternation of Generations. 
¢.g., Apis, Nematus. 
(2) Alternation of Sexual and Parthenogenetic Generations 
— Heteroparthenogenesis (Hatschek), Hetero- 
geny (Leuckart), Pseudoparthenogenesis (Spen- 
cer). 
e.g., Aphis, Daphnia. 
The following classification of Complete Parthenogenesis is based 
on the sex of the resulting individuals : 
1. Homoparthenogenesis (Henneguy), Complete Parthenogenesis 
(Spencer). 
One sex only produced from unfertilized eggs. 
(a) Arrenotoky (Leuckart),«Androgenetic (Breyer). 
Males produced. ¢.g., Apis. 
(6) Thelytoky (v. Siebold), Gynogenetic (Breyer). 
Females produced. e.g., Psyche. 
2. Heteroparthenogenesis (Henneguy), Mixed Parthenogenesis 
(Stein). 
Amphoterotoky (Taschenberg), Amphotoky (Lankester). 
Both sexes produced parthenogenetically. ¢.g., Aphide. 
An Alternation of Generations often accompanies partheno- 
genetic development, and in the literature considerable confusion 
occurs by a mixing of the terms. For this reason the following 
classification is given so that the occurrence of Parthenogenesis in 
relation to Alternation of Generations may be made clear: 
Alternation of Generations (Metagenesis Owen). 
1. Sexual Generation alternating with a Budding Generation. 
(a) Buds remain attached to form colonies. 
e.g., Medusz and Polyps. 
(6) Buds separate. 
é.g., Salpa. 
2. Sexual Generation alternating with Parthenogenetic Generation. 
Heteroparthenogenesis (Hatschek), Heterogeny (Leuckart). 
