FUKSII-WATKU ALd.fi OF T I! I! C M T I! H STATES. 107 



/,' //id //..-. - This species is probably widely diffused through the temperate por- 

 tions of North America. I lia\e found it abundantly near Philadelphia, as well as 

 among the Alleghanics, and ha\e received specimens from Dr. Lewis, collected in 

 5 o Lake, Northern New York ; Prof. Bailey also notes it as occurring in Georgia. 

 There is one form of it which resembles somewhat in outline the modern coffin, 

 one end In-ing much broader and much more rapidly narrowed than the other. 

 There is no distinct vucuolc at the end, at least in any specimen I remember to 

 have seen, although frequently large numbers of moving granules can be detected 

 in that portion of the frond. 



i'ig. (i, pi. 'JO, represents the outline of a frond of this species. 



P. lamrlloMiiiii, r.ui.ii. 



1'. cflluli* oblongo- vcl fusiformi-cylindricis, diamutro 6-6 plo longioribus, medio ssepe levitcr 

 con.-tririis, utruque polo magis atteuuatis, obtuso rotuudatis. (It.) 



Uium.O 0023" 0.0029". (R.) 



v /'. lamellosum, BBEB. RABENHOKST, Flora Europ. Algarum, Sect. III. p. 118. 



//,i/,._Rhode Island (Olney) Thwaites. 



Cells oblong or fusiform cylindrical, 5-6 times longer than broad, often slightly constricted in 

 the centre, more attenuate at the ends, obtusely rounded. 



Remark*. I have never recognized this species, but it is one of those sent over 

 l'\ Mr. Olney, and identified by Prof. Thwaites. 



6. Lamina chlorojihyllcu-ea integerrima. 

 b. Chlorophyl lamina entire. 



* Cellulte in media jrfus minus constrictte. 



* Cells more or less constricted in the middle. 



P. mar^aritacenm, EIIRB. 



I*. r|cni!;iitii cylindricum, diametro 8-9 plo longios, medio plernmquo leviter constrirtuni, utroqne 

 polo rotundato-truncutum ; cellule mcmbrana nodulis seriatis quasi margariUtcca ; locellus 

 in medio (circiter) atriasque craris corpusculis mobilibus in more Closteriorum replctus. (R.) 



Diam. 0.00098" 0.0011". (R.) 



Hub. Rhode Island. (Olney) Thwaites ; Bailey. Florida. Bailey. 



Elongate cylindrical, 8-9 times longer than broad, in the centre generally slightly constricted, 

 at each end roundly truncate ; membrane of the cells somewhat pearly with seriate granules; 

 vacnole about in the centre of each eras, filled with moving grannies, as in closterinm. 



Remarks. I have not seen this desmid, but it is in Prof. Bailey's list; it was 

 also among those sent by Mr. Olney to Prof. Thwaites. 



P. iiiiiiuf mil. CLEVK. 



1'. cylindricum, gracile, diametro 5-7 plo longins, laeve, ad polos obtusissimos (latissime rotnn- 

 datos) parum attenuatum, medio leviter constrictum. (R.) Species mihi ignota. 



Diam. 0.00044" 0.00063". (R.) 



8yn. Docidium minutum, HALF'S British Desmid. 



P. minutum, CLKVE. RABKNHOROT, Flora Enrop. Algarum, Sect. III. p. 122. 



