264 



ZOOLOGY 



The Copepoda are divided into two sub-orders : (i.) the 

 Branchiura, which includes the two genera Argulus and Gyro- 

 peltis ; and (ii.) the Eucopepoda, which embraces the mass of 

 the Copepods, both free-swimming and parasitic. 



(i.) The Branchiura are known as Carp -lice, Argulus 

 being parasitic upon Carp and Sticklebacks. These animals 

 differ considerably from the members of the Eucopepoda. In 



Pig. 157. — Argvlus foliaoevs, female, 

 seen from the ventral side. After Jurine. 



Pointed rostrum. 



Antennules. 



Antennae. 



Eye. 



Sucker on anterior ramus of 2nd 



maxilla. 

 Liver. 

 Ovary. 



Eggs leaving the body. 

 Posterior ramus of 2nd maxilla. 



Argulus the mouth is prolonged into a suctorial tube, within 

 which lie concealed the serrated mandibles and styliform 

 first maxillae : a modification of the mouth parts which is 

 common amongst certain orders of Insects. In front of the 

 mouth is a styliform weapon, which also lies in a sheath. The 

 second pair of maxillae, the so-called maxillipedes, ares modified 

 to form organs of adhesion, the anterior ramus taking the form 

 of a sucking disk, the posterior being hooked. Behind these 

 are found four pairs of swimming legs, all of them, except the 

 last, concealed by the body. The abdomen terminates in 

 two caudal plates ; the whole body is flattened dorso-ventrally. 

 The male is more active than the female, and possesses copu- 

 latory appendages on the last thoracic limbs ; the eggs are not 

 carried about in the usual Copepod fashion, but are deposited 

 upon surrounding objects. 



