In the Rotifera the sexes are separate and the emancipation of the female 

 is quite complete. She may live her whole life and produce innumerable off' 

 spring without ever meeting a male. As a matter of fact, males are very rare, 

 small, and lack mouth and stomach. They usually occur in the autumn and 

 mate with the females who then produce a special type of egg which survives the 

 winter and produces females for the next spring. During spring and summer 

 these females produce eggs which hatch without fertilization into more females. 

 In the autumn, smaller, male-producing eggs are also laid. This process of 

 development without fertilization is called parthenogenesis and is fairly common 

 among invertebrate animals. 



Another odd group of animals, often classed with the rotifers and likely 

 to puzzle the amateur microscopist, is the Castrotricha. The name comes from 

 two Greek words meaning ''hairy stomach" and refers to the ciliated ventral 

 surface. These animals are widely distributed and are usually present wherever 

 Protozoa and rotifers are found. Occasionally they get to be twice as long as 

 a Paramecium but are usually about the size of, and are commonly mistaken 

 for, large ciliate Protozoa. They are usually covered with small scales or with 

 spines. They generally have two posterior toes, as do many rotifers, but lack 

 the telescoping foot. Little is yet known of the American forms and their 

 habits. 



OUTLINE OF CLASSIFICATION OF CASTROTRICHA 

 Order CHAETONOTOIDEA 



Marine or fresh-water animals with one pair of cement tubes posteriorly 



or with none 



Family CHAETONOTIDAE 



Rear end forked; v^'ith one pair of cement tubes 

 Three genera — Lepidoderma 

 Chaetonotus 

 Ichthydmm 

 Family DASYDYTIDAE 



Rear end rounded; no cement tubes 

 One genus — Dasydytes 

 OUTLINE OF CLASSIFICATION OF THE ROTATORIA 

 (or Rotifera) 

 Class BDELLOIDEA 



With paired ovaries; no male animals 

 Family ADINETIDAE 



Corona flat, with cilia on the ventral side 

 Common genus — Admeta 

 Family PHILODINAVIDAE 



No corona ;with a bunch of cilia in the mouth region 

 Common genus — Philodinavus 



61 



