178 Uinversiiii of CaUfoniia PuMirations in ZooJogn [Vol. 16 



Most of the specimens examined belonged to Calamis finmarchicus 

 and the facts about the intestinal contents of that form, as I found 

 them, are as follows. It happens that in a third of the eases the tube 

 had no contents at all. Practically all of the other specimens, however, 

 showed a green or greenish-yellow mass of varying extent. In some 

 it filled the intestine, in others there was only a small bit, but the 

 characteristic color was present. The colored mass, even under the 

 oil-immersion, was homogeneous, except for broken bits of diatom 

 shell and particles of detritus and mineral matter. 



The recognisable remains of organisms in the gut of Calanus con- 

 sist chiefly of the shells of diatoms, of which Coscinodiscus is the most 

 abundant. Broken or entire shells occur in most cases when diatoms 

 are present at all. It is hard to estimate the numlber of specimens 

 when the shells are broken ; I saw one or two entire tests, and frag- 

 ments are more abundant. In three eases there were masses of broken 

 Coscinodiscus shells, and evidently the plants had been ingested in 

 large numbers. Usually, however, the number of pieces, even, is 

 under ten. Another diatom that occurred frequently was one of the 

 Thalassiothrix type, but the shells were not found as often as those 

 of Coscinodiscus. In several instances the intestine was packed full 

 of pieces of Thalassiothrix. The diatoms Planktoniella and Navicula 

 occurred, also, the former in one copepod and the latter in two. 



Eleven specimens of Calanus contained fragments of a silico- 

 flagellate closely resembling Dictyocha (if not that form) but not 

 over four of the pieces were seen in one animal. 



It is interesting to find that Calanus ingests the Coccolithophores. 

 Gran (1902, p. 163) observed the plates in the fecal capsules of cope- 

 pods, and Murray and Hjort (1912, p. 382, 719) also mention that 

 the plates occur in the capsules. Nineteen specimens of Calanus that 

 I examined had the coccoliths in the intestinal contents. The numbers 

 varied widely ; in some the intestine was literally packed with them, 

 but usually there were not many. There were twenty entire organisms 

 in one copepod, nine in another. The coccolithophores belong almost 

 entirely to that group which has the perforated coccoliths (Lohmann, 

 1902, p. 127), but I saw two with the rodlike coccoliths. The one com- 

 monly found is much like the drawing of Pontosphaera hii.rleyi as 

 shown in plate 4, figure 3, of Lohmann 's paper (1902). 



Other organisms were found to occur in the gut of Calanus. A 

 species of Dinnpkys.is was found in five specimens, one of which con- 

 tained two of the cells. Prorocentrum (probably P. micans) was 



