54 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



the inside row, which are about twice as long as the others; the sub- 

 circular central portion, about one-half the diameter of the valve, is 

 obscurely covered with wrinkles, a median longitudinal one being the 

 strongest; a prominent bead is set in the outside rectangular row at 

 each end of the valve, marking the two polar areas. 



Width, 0.099; length, 0.096 mm. 



Type.— Cat. No. 43604, U.S.N.M. 



CAMPYLODISCUS PFITZERI A. Schmidt 



See O. horologium Williamson. 



Although De Toni thinks this worthy of mention as a variety of 

 C. horologium, I do not see any appreciable difference between the 

 two. It is figured in Schmidt's Atlas, plate 17, figures 5-6. 



CAMPYLODISCUS PHALANGIUM A.Schmidt 



(Schmidt, Atlas, pi. 14, figs. 11-12; pi. 93, figs. 16-17; Deby, Campy., pi. 5, 

 fig. 24c.) 



I agree with Deby in recognizing this as separate from C. brown- 

 eanus Greville, of which De Toni (Syl. Alg., p. 620) makes it a 

 variety. It is another form peculiar to Campeche Bay and the 

 Philippine Islands. 



CAMPYLODISCUS PUNCTULATUS Grunow 



(Schmidt, Atlas, pi. 17. fig. 4.) 



This well-marked species is another example of the diatoms pecu- 

 liar to both Campeche Bay and the Philiphine Islands. 



CAMPYLODISCUS RABENHORSTIANUS Janisch 



(Janisch and Rabenhorst, Diat., Hondur., p. 6, pi. 1, figs. 6-7; Schmidt, Atlas, 

 pi. 53, figs. 12-14; Deby, Campy., pi. 9, fig. 46.) 



Although not a strictly Campeche Bay form, it is approximately 

 so, being abundant on the coast of Honduras. 



CAMPYLODISCUS RALFSII W.Smith 



(Smith, Brit, Diat., pi. 30, fig. 257; Schmidt, Atlas, pi. 14, figs. 1-3; Deby, 

 Campy., pi. 2, fig. 18.) 



As mentioned under C. decorus Brebisson, I do not favor uniting 

 these two. But C. scalaris Tempere and Brun (Diat. Jap., pi. 4, fig. 

 12) seems to be only a variety of this form. 



CAMPYLODISCUS RATTRAYANUS Deby 



(Deby, Campy., p. 36; Schmidt, Atlas, pi. 18, fig. 10.) 



The type, according to Deby and represented by the above figure 

 of Schmidt, is from Brazil; but C. schmidtii Grunow, figured in 

 Schmidt's Atlas (pi. 53, fig. 10), is possibly the same diatom and 

 comes from Campeche Bay. 



