CAPRELLA 39 



Class: Crustacea. Division: Malacostraca. Order; Amphipoda 



CAPRELLA 



This is a very common marine amphipod which is found along 

 our shores cHnging to hydroid colonies or to seaweed. It is an 

 interesting animal because it illustrates an extreme degree of 

 modification from the typical amphipod type, — a modification 

 which is the result of its mimicry of the form of the hydroid or 

 seaweed on which it lives. 



Notice the irregular, cylindrical form and the small number of 

 appendages. The apparent head is composed of seven fused 

 somites, of which five are cephalic and two are thoracic, the first 

 of these latter bearing a pair of maxillipeds, and the second a pair 

 of legs. There are thus six free thoracic segments, of which the 

 first, fourth, fifth, and sixth bear legs which are without gills and 

 the second and third bear gills but no legs. The abdomen has lost 

 its segmentation and its appendages and has been reduced to a 

 mere protuberance at the end of the thorax. 



Exercise. Draw a large outline of the side view of the animaL 

 Number the segments and label the parts observed. 



