NO. 1 BARNARD : AMPHIPODA OF THE FAMILY AMPELISCIDAE 35 



Material examined: Stations 281-34 (1), 439-35 (2), 468-35 (1), 

 769-38 (6), 770-38 (3), 1168-40 (3), 1169-40 (6), 1191-40 (1), 

 1194-40 (6), 1202-40 (1), 1220-40 (1), 1321-41 (17), 1388-41 (2), 

 1390-41 (6), 1780-49 (8), 2018-51 (3), 2026-51 (4), Burch 3837 (1). 



Remarks: This species is closely related to Ampelisca brevicornis 

 (Costa, 1853) but is distinguished by the lack of a strongly produced 

 article 4 of peraeopod 1, by the smaller posterior lobe of peraeopod 5, 

 by the long article 2 of peduncle of antenna 1, and by the straightness of 

 the posterior edge of article 2 of peraeopod 4. In some of these characters 

 it is more closely related to A. subbrevicornis Pirlot ( 1936) ; but it differs 

 from that species in the shorter length of article 5 of the peduncle of an- 

 tenna 2, the longer, more slender article 2 of the peduncle of antenna 1, 

 the lack of a strongly developed posterior lobe of article 4 of peraeopod 

 5, and the subequal rami of uropod 3. 



Distribution: Along the coast of southern California and in the Chan- 

 nel Islands, 16 to 83 fms; along the coast of Lower California at Cedros 

 Island, Santa Maria Bay, and Blanca Bay, 8 to 30 fms; Gulf of Cali- 

 fornia off San Gabriel Bay, Espiritu Santo Island, 21 fms; off San 

 Jose Point, Guatemala, 7 to 20 fms; Port Parker, Costa Rica, 5 fms; 

 Pinas Bay, Panama, 20 fms. 



Ampelisca panamensis, new species 

 Plate 25 



Description of female: Head similar to Ampelisca cristata Holmes, 

 nearly as long as first 3 body segments, lower front margin parallel to 

 upper margin ; lower pair of eyes at inferior angle, upper pair smaller 

 than lower pair, behind upper margin of antenna 1. 



Antenna 1 reaching end of peduncle of antenna 2; article 1 stout, 

 tumid ; article 2 nearly twice as long as article 1 ; article 3 shorter than 1. 



Antenna 2 about two thirds as long as body; article 5 of peduncle 

 three fourths as long as article 4. 



Mandible with 8 to 10 spines in spine row; article 3 of palp two 

 thirds as long as article 2. 



Maxilla 1 : outer plate with 1 1 spine teeth ; palp narrower than 

 outer plate, apex with 7 spines and 8 to 10 setae. 



Maxilliped: inner plate very broad, reaching slightly beyond palp 

 article 1, apex strongly setose, with a single, chisel-shaped spine; outer 

 plate reaching to end of palp article 2, inner edge with 8 chisel-shaped 

 teeth, apex with 4 setal spines, outermost one plumose. 



