ART. 15 COPEPOD CRUSTACEANS OF CHESAPEAKE BAY WELSOK 51 



Remarks. — Though captured swimming freely this copepod lives 

 commensally within some species of Salpa. According to Giesbreclit 

 it uses S. deniocratica as a host, but Wheeler's specimens were taken 

 in company with S. cordiformis. 



SAPPHIRINA SINUICAUDA Brady 



Sapphirina sinuicanda Brady, Challenger Expedition, Copepoda, vol. 8, p. 129, 

 pi. 49, fig.>-'. 7-10, 1883. — GiESBBECHT, Fauna und Flora des Golfes von 

 Neapel, vol. 19, p. 648, pi. 52, figs. 31, 33, 34 ; pi. 53, tigs. 42, 50 ; pi. 54, tigs. 

 26, 36, 70, 1892. 



Occwrence. — ^About 40 specimens of this species were taken in a 

 bottom net at the 100-fathom line in the outside ocean; none were 

 found within the limits of the bay. 



Remarks. — Like >S'. gemma, this is also a pelagic form and not 

 likely to be found within the limits of the bay. Thus far all the 

 specimens have been captured while swimming freely, but like other 

 species of the genus it is probable that the present one lives com- 

 mensally within some species of Salpa. 



Suborder CALIGOIDA 



CALIGUS SCHISTONYX Wilson 



Caucus schistonyx Wilson, Proc. U. S. Nat. Mus., vol. 28, p. 564, pi. 6, figs. 

 6&-78, 1905. 



OcGurrenoe. — Several specimens were obtained in the surface net 

 at Station G in the mouth of the bay on October 21, and in the 

 vertical net on December 4, 1920. Others were captured in both 

 surface and bottom nets at Station C on October 20, 1920. All the 

 specimens taken were swimming freely in the tow. 



Remarks. — Of the 15 lots of this species already in the collection 

 of the United States National Museum, 9 were obtained from the 

 tow. This species is very often captured when swimming freely, 

 probably because it is an external parasite on the common menhaden 

 {Brevoortia tyrannus). These fishes serve as the prey or food of 

 other fishes, and while being caught and eaten some of their external 

 parasites would naturally be set free in the water. 



