Apus. 29 



and go on gradually increasing, till, at the end of three 

 weeks, they have reached the size of one inch in length. 

 The process of moulting, or changing their skin, takes 

 place about twenty times in the space of between two and 

 three months, at which time they seem to have attained 

 their full size. Schceffer says, he never witnessed the pro- 

 cess of moulting so as to be able to describe the mechanism, 

 but it no doubt is the same as will be more fully described 

 hereafter, when treating of the Daphnise. 



SchoefFer performed several experiments upon the Apus 

 to ascertain whether it possessed the faculty of repro- 

 ducing mutilated members. He found it had not, and 

 that after moulting, the truncated members remained 

 shorn of their fair })roportions. It appeared, however, 

 that the excision of one or two of its feet, or part of its 

 rami, produced no bad consequences to the health of the 

 individual so treated. 



This family contains only one British genus — Apus. 



Genus Apus.* 



Attovc, Frisck, 1732. 



Apus, Schoeffer, Lafreille, Bosc, &c. 



MoNOCULUS, Linnceus, Fabricius. 



BiNOCULUS, Geoffroy, Leach, Diet. Sc. Nat., xiv, 538. 



LiMULUS, Miiller, Lamarck. 



TmoPES, Schrank. 



Character. — As this family at present contains only 

 one genus, the characters given to it will be sufficient for 

 the genus also. 



* A, privitive ; and ttoi^c, a foot. 



