43 

 Falls and Faterson down the river but above tide water mark. It is 

 found below the f^assaic Falls at Paterson, at five miles and a half 

 at a place cailed Aquakinonk. At Paterson the River makes a perpen- 

 dicular fall of fii'ty feet and one of sixteen feet so that at least there 

 is one hundrcd and seventeen feet of fall. As Hatfield Swapm is 

 twelve and a half miles from Paterson and five miles from tide 

 water at Aquackinonk there at least seven and a balf, and Cooke's 

 Bridge is two and a half further up there are twenty miles to tide 

 water a fall of one hundred and seventeen feet between. So that it 

 cannot be said that Aclinocycìus is washed up from salt water. In 

 fact it is fresh water. Ralfs makes the two species with three to one 

 hundred and twenty rays, one hundred and eighteen species, or 

 forms, into one and calls it A. Ehrenbergii, but makes another spe- 

 cies A. Ralfsii, which is Eupodisciis Rai/sii of \V. Smith and descri- 

 bes three other species as A. moniliforniis. A, fulviis and A. crassus. 

 The marking of ali of these are in circular scompartments alike. The 

 disc is said to be iridescent but somctimes it is transparent. This 

 iridescence is scen in the Hatfield Swamp specimens to be due to 

 the prescnce of two membianes for after they are partially separated 

 and somelimes one alone exists, so that the specimen presents three 

 kinds of iridescence when the membrane, internai or external, is 

 partially removed and when one of them is entirely removed so 

 that the specimen seems transparent. There is no pseudo-nodule 

 present as is seen in the species monilìforiììis, Ehrenbergii, Ralfsii, 

 and crassus. And the markings are variablc, sometimes closely ra- 

 diant and sometimes with blank spaces in them and even some- 

 times arranged in curvcd rays. The number of rays also varies. 

 From this I cannot sec how the one hundred and three are not 

 one and I should cali it by the first name that was published, na- 

 mely Aclinocycìus leniarius, C. G. E. which is described in the 

 Abhandlungen for i832, pag. 129, T. 4, fig. III. 



Ainpììiprora elegans, W. S. One specimen of a form that looks 

 like this species but A. elegaus is a marine species and differs frorn 

 A. vitrea by beìng « more lanceolate and stender frustules closeer 

 striae ». It looks like A. lepidopiera, W. G. which is found in the 

 mud of the Clyde, Scotland. These species ali look alike. 



A.ì navicularis, C. G. E. 1848, Ab. p. 122, This species, although 



