1916] Esferh/: Feeding Habits of Prlagic Coprpods 179 



found in seven specimens, one of which contained 63 of the protozoans 

 and another twelve ; the intestine in the former case was closely 

 packed with the cells. Peridinium was recognised in seven, two of 

 them in one copepod ; in this particular case the cells had retained 

 their shape but were without contents, while in the others the tests 

 were wrinkled and distorted yet recognisable as those of some Peri- 

 dinium. Mangin (1911, p. 45) has noted the effect of the digestive 

 processes of various animals on Peridinium. One Calanus contained 

 the skeleton of a nauplius, and in three instances there were the 

 broken bristles of some crustacean. 



Eucalanus elongatus. — This copepod is abundant in the San Diego 

 region, ranking next to Calanus. Eucalanus is exceedingly trans- 

 parent, so that the entire digestive tract can be seen through the exo- 

 skeleton and muscles. I have examined numbers of this copepod both 

 living and in serial sections, and have never seen the recognisable re- 

 mains of any ingested organism. Most specimens, in fact, are devoid 

 of any intestinal contents, though in two cases I have seen a fecal 

 capsule in the posterior part of the tract ; the capsule, however, con- 

 tained only a colorless granular mass of homogeneous character. 



Scolecithri.r persecans. — This copepod is notable because in all of 

 the seventeen specimens the intestinal contents were abundant. All 

 of the animals contained crustacean bristles, and in some instances the 

 gut was packed with them. Many of the bristles were those of some 

 copepod, but it is certain that there were the remains of other Crus- 

 tacea. The tract of several specimens were filled with a red-brown 

 mass of finely granular material in which the bristles were contained. 

 Two specimens of this copepod had ingested Coscinodiscus in small 

 numbers. 



Pleuromamma quadrungulata. — Fifteen specimens were examined. 

 In six the tract was empty except for a few scattered mineral par- 

 ticles. Of the others, one contained a piece of a radiolarian test, three 

 had broken bristles of some sort, and five showed traces of the greenish 

 material. 



Plevronwmma abdominalis. — Out of fifteen specimens, there were 

 seven whose intestinal tracts were empty, while six had more or less 

 of the green color. Among the organisms recognised were the diatoms 

 Synedra, Thallasiothrir, Fragilaria and Coscinodiscus, all as frag- 

 ments; Dictyocha; Glohigerina; broken bristles of a copepod. In no 

 case was the tract even moderately full. 



