1911] Esterly: Copepoda of tht San Diego Region. 315 



Tin-re are some points about the two species I have recorded 

 as belonging to Aetideopsis Sars, in which they do not agree 

 with the descriptions of Sars, but I can see no valid reason for 

 not including the San Diego specimens in that genus. 



Aetideopsis pacifica, n. sp. 



PI. 28, figs. 24, 25, 30; pi. 31, figs. 80, 103; pi. 32, fig. 113. 



Adult female. Tlie head is smoothly rounded and the rostrum 

 is strong and heavily chitinised (pi. 28, tigs. 24. 25). The prongs 

 of the rostrum do not curve backward very much and arc set 

 close together at the base; they do not diverge much from the 

 base (pi. 28, fig. 30). 



The sides of the last thoracic segment are produced into sharp 

 projections and the head is fused with the first thoracic segment; 

 the fourth and fifth thoracic segments seem to be fused, though 

 there is a very distinct line visible between them everywhere (pi. 

 28, fig. 24 i. This is shown better in fig. 31, which is of A. divari- 

 cata. The abdomen is 4-segmented and, with the furca, is be- 

 tween one-fourth and one-fifth as long as the cephalothorax ; the 

 first segment is longer than any of the others and the second seg- 

 ment is about as long as the third and fourth together. 



The anterior antennae are 23-jointed and do not extend back 

 to the end of the cephalothorax. The posterior antennae and 

 mouth parts do not show any peculiarities, unless the slender 

 form of the posterior maxillipeds, which is characteristic of the 

 genus, is mentioned (pi. 32, fig. 113). The first foot (pi. 31, fig. 

 86), has a 3-jointed outer ramus, each joint with an outer mar- 

 ginal spine. The inner ramus of the second foot is 2-jointed; 

 that of the third and fourth feet is 3-jointed. The teeth on the 

 serrate bristle of the outer rami in the second to fourth pairs of 

 feet are characteristically arranged (pi. 31. fig. 103). 



Length: 3.18 nun. 



Coloration: Opaque white in formalin. 



Occurrence: Station 1252, tow at, and vertical from. 310 f., sounding 

 345 f.. July 11, 1906; station 1303, tow at, and vertical from, 315 f., sound- 

 ing 340 f., July 18, 1906. 



