HAWAIIAN ACANTHURID CALIGOIDS — LEWIS 225 



The moult of the form described as the older early encystment 

 stage was frequently found in empty cysts. One of the specimens 

 included in the collection deposited in the U.S. National Museum was 

 moulting when preserved. The moult of this specimen was that of the 

 older early encystment stage, the specimen was in the late encystment 

 stage; no additional moults were observed in the cyst. The moult 

 suggests that at least two stages are passed within the cyst. Whether 

 or not the copepod encysts more than once during its development 

 has not been determined. A specimen in the late encystment stage 

 was removed from its cyst and kept alive for seven days, during which 

 time no change occurred in the animal. 



Live copepods, when removed from their cysts, were extremely 

 flexible. This condition is presumably useful during excystment, 

 when the animal backs out of the opening at the end of the ovoid cyst. 

 The opening was present in all of the cysts examined and the tips of 

 the caudal rami of the copepod were observed protruding from the 

 opening. Since copepods purportedly have anal respiration (Wilson, 

 1905), it appears that this opening serves for respiration and excretion. 



All of the type specimens of Nesippus costatus Wilson, 1924, and the 

 only specimens known for this copepod, have been lost. For this 

 reason, definite identification of the copepod described here is impos- 

 sible. The similarity of the late encysted and recently excysted 

 forms to the description of the male of A'', costatus given by Wilson 

 (1924) indicates that the specimens described here are probably spec- 

 imens of this species. The differences between the described specimens 

 and the male of A^. costatus are given in the preceding description. 



Family Anthosomatidae 

 Genus Norion Nordmann, 1864 



Diagnosis. — Body ovoid, strongly flattened dorsoventrally. Body, 

 except cephalon, maxilliped-bearing segment, and first thoracic leg- 

 bearing segment, covered with shield consisting of single dorsal plate 

 over posterior surface, pah-ed dorsal plates over anterior surface, and 

 single pair of ventral plates, modified second thoracic legs, covering 

 posterior ventral surface. Single posterior dorsal plate and ventral 

 plate pair-forming brood pouch. Abdomen small, ovoid. Eggs in 

 uniseriate strings curled inside brood pouch. Antennule seven- 

 segmented; first pair of thoracic legs reduced, second pair forming 

 ventral plates, third pair lamelliform, fourth pair dactyliform pro- 

 topodite with rami reduced to minute lobes. Caudal rami obovate. 



Remarks. — Nordmann erected this genus for the species A^. exjMii- 

 sus on the basis of a single specimen from the gills of an unknown fish 

 captured in the Hawaiian Islands. The genus was placed by Nord- 



