REPORT ON THE DIATOMACEiE. 63 



The specific name lias reference to the locality in which the form was first 

 collected. 



Campylodiscus bicinctus, n. sp. (Plate XI. fig. 2.) 



Valvse subrotundae, epbippiformes, duplici brevium costularum corona aream ellip- 

 soideam includente. E mari Japonico. 



This somewhat larger valve exhibits a large smooth rotundato-elliptical central area, 

 which is surrounded by a double row of short radial costules, the rows being separated by a 

 smooth narrow ring. As in the preceding case, the two poles present indications of the 

 development of new costules. 



The presence of a double row of enveloping costules has been made use of in naming 

 this type. 



Campylodiscus erosus, n. sp. (Plate XL fig. 3.) 



Valva discoidalis, ephippiformis, costis subradiantibus numerosis prope marginem 

 circum divisis ad aream sublinearem terminantibus ; costularum pars centralis evanescens 

 et quasi usu attrita. Ad oras Japonicas. 



The present frustule bears some analogy to that last described. It possesses a double 

 corona of costules, of which those round the periphery are short, while those situated more 

 centrally are three times larger than the former in the middle, but diminish somewhat 

 irregularly towards the poles. The smooth central area is long and narrow. 



From the circumstance that the intermediate parts of the inner series of costules are so 

 slightly manifest as to appear as if they had been subjected to attrition, the specific name 

 of erosus has been given. 



&* 



Campylodiscus erosus, n. sp. var. nov. (Plate XI. fig. 5.) 



We have here represented a frustule from the Sea of Japan, in which most of the costules 

 of the inner series are represented by two oblong cellules. There can be no doubt that 

 this is but a further stage of the attrition which is manifested in Campylodiscus erosus, 

 so that nothing remains of the costules except the two extremities. Hence, although 

 apparently very distinct characteristics are here found, these can only be regarded as 

 possessing a varietal significance. 



Campylodiscus lepidus, n. sp. (Plate XL fig. 7.) 



Forma subrotunda, mediocris ; costulis circumradiantibus a corona irregularium lineo- 

 larum, quse aream late ellipticam includit ; costulse lateraliter partim linea, partim spatio 

 quadratim punctato circumscribuntur ; margine granulorum linea signato, exterius spinuloso. 

 In mari Philippinarum. 



