360 THE INVERTEBRATA 



Caprella (Fig. 267), slender-bodied and living upon seaweeds, 

 hydroids. etc., has two thoracic somites in the cephalothorax, no 

 legs on the 4th and 5th thoracic somites, all the remaining legs 

 subchelate, and the abdomen reduced to a minute stump. 



Fig. 265. Fig. 266. 



Fig. 265. Mouth parts of Gamwan/s. A, Mandible. B, Maxillule. C, Maxilla. 

 D, Maxillipeds. en. endopodite; inc. incisor process; la.mo. lacinia mobilis; 

 mol. molar process; pip. palp; spi. spine row; 1-3, segments of limb. 

 Fig. 266. A diagram of a transverse section through the thorax of Gammarus . 

 br. branchia; bp. basipodite; cp. coxopodite; cp.' coxal plate; g. gonad; 

 h. heart; hep. "hepatic" coeca; int. intestine; n. nerve cord; 00. oostegite. 



th.3. 



Fig. 267. Caprella grandimana. From the Cambridge Natural History, after 

 P. Mayer, ab. abdomen; br. gills; th.2, th.S, thoracic somites. 



Cyamus, the whale louse, is a Caprella with a short, wide body, 

 adapted to its habit and habitat. 



