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MANUAL OF ZOOLOGY. 



aceous or leaf -like, branchial in function. The eyes sometimes con- 

 fluent, sometimes distinct and sub-pedunculate. There are two 

 horny mandibles without palps, and the first pair of feet are 

 oar-like, with setiform terminal appendages. The remaining 

 feet are branchial, and adapted for swimming. The Phyllo- 

 pods undergo a metamorphosis, the youngest forms being 



Fig. 146. Phyllopoda. Fairy Shrimp (Chirocephahts, or Branchip^ts, diaphanus). 

 After Baird. 



"Nauplii." In Nebalia (fig. 147, C), however, which is the 

 only marine Phyllopod, " Zoea-stages " are superadded as well. 



B 



Fig. 147. Morphology of Phyllopoda. A, Lepidurns Angassi, viewed dorsally. B, 

 Under side of head of the same. C, Nebalia bipes, one side of the carapace being 

 removed, so as to show the branchial feet. D, Branchipus stagnalis, female. E and 

 F, Young stages of the same. G, A magnified specimen of Estheria, in its living 

 state. 



The Phyllopoda are chiefly interesting from their affinity to the extinct 

 Trilobites. In the typical genera Limnadia and Apus the body is pro- 

 tected by a carapace, which is bivalve in the former and shield-like in the 

 latter. In Limnadia the carapace covers the greater part of the body, and 

 opens along the ventral margin. There are from eighteen to thirty pairs 

 of membranaceous and respiratory feet. In Apus the carapace is clypei- 

 form and covers a portion of the abdomen ; and there are sixty pairs of feet, 

 of which all but the first pair are foliaceous. Apus is gregarious, fresh- 



