ART. 15 COPEPOD CEUSTACEANS OP CHESAPEAKE BAY WILSON 43 



Remarks. — This was the most widely distributed species of Gory- 

 caeus in the bay, but like all the others it occurred only in very small 

 numbers. It is quite different from the other species in dorsal view 

 and may be recognized without much difficulty. 



CRYPTOPONTIUS GRACILIS, new species 

 Plate 4, J-S 



Specific characters of female. — Anterior body broadly expanded 

 but not strongly deptessed, with the epimeral lappets close together 

 and curved backward. Cephalothorax as wide as long and about a 

 fifth longer than the remainder of the body, broadly rounded in front 

 with no dorsal crista; rostral projection minute. Lappets on the 

 second and third thoracic segments broad and pointed, those on the 

 third segment not reaching the center of the genital segment. Lap- 

 pets of the fourth segment very small and conical in form, almost 

 wholly concealed in dorsal view. Fifth segment very short and nar- 

 row and without lappets. Anterior half of genital segment dilated 

 laterally to nearly twice the width of the posterior half. Abdomen 

 with three segments, decreasing in width, but increasing in length 

 posteriorly. Caudal rami as wide as long and rounded at the tip, 

 each carrying five setae, of which the second from the inside is the 

 longest and the second from the outside is the shortest. 



Anterior antennae with nine segments, of which the second is short 

 and the third and ninth quite long. According to Giesbrecht's in- 

 terpretation the long third joint represents segments 3 to 8 fused, the 

 fourth joint segments 9 to 11 fused, the fifth joint the twelfth seg- 

 ment, the sixth, seventh, and eighth joints three segments each, and 

 the ninth joint segments 22 to 25 fused. On this basis the large 

 aesthetask, which is two-thirds as long as the entire antenna, is 

 attached to the twenty-third segment. 



The posterior antennae are 4-segmented, the second and fourth 

 joints about equal and much longer than the first and third, the 

 middle terminal seta stout and rigid. The rudimentary exopod 

 is rather large and is tipped with a single seta. The mouth tube 

 is slender and extends nearly to the posterior margin of the cephalo- 

 thorax; its basal portion is a little more than six times as wide 

 as the terminal. The outer lobe of the maxilla is two-thirds as long 

 as the inner, with a single stout apical seta, while the inner lobe 

 ends in a minute seta. The terminal segment of the second maxilla 

 is but little longer than the basal and enlarged at its tip, with a 

 short and stout terminal claw. The terminal claw of the maxilliped 

 is stout and is not so long as the second and third joints combined. 



Specific characters of male. — Cephalothorax a fifth longer than 

 wide and also a fifth longer than the rest of the body. The first 

 antennae have ten segments, with aesthetasks of half the length of 



