18 PROCEEDINGS OF THE ACADEMY OP 



other, (pi. ii., fig. 20,) is a not uncommon coastal species. Both are brackish. 

 For convenience of reference, I have provisionally named these forms, whose 

 claims to rank as distinct species are very questionable : 



(1.) Navicula incomperta, (pi. ii.. fig. 20.) Y. lanceolate elliptic, with a 

 thick double median line; terminal nodules inconspicuous; transverse stria 

 parallel; about 70 in 00l // ; longitudinal strix wavy, faint, about 55 to 60, in 

 001. Cape May, Atlantic, and Rockaway Salt marshes, common. 



(2.) Navicula intkrposita, (pi. ii.,fig. 19.) V. elliptic, elongated, shorter than 

 in the preceding; terminal nodules usually inconspicuous. Transverse strice 

 sharp, parallel, about 50 a 55 in 001 // . Longitudinal, straight, parallel, about 45 

 a 50 in -001. Paraiba Harbor, S. A. ; Wilmington R., Savannah, Ga. C. 

 Febiger. 



The front view of both these species is linear, or sometimes slightly con- 

 stricted, with abruptly rounded ends, to which the suddenly inflected terminal 

 nodule gives an emarginate appearance, as is sometimes seen ia N. rhomhoides. 



In N. Lewisiana, on the other hand, the front view is commonly a little infla- 

 ted, and the terminal curves much more gradual. The straight and long ter- 

 minal nodule of this last species, subtends the arc formed by this curve, 

 whence, probably, arises a good deal of that apparent inflation of the " extra 

 median" lines, spoken of by Dr. Greville. (Trans. Mic. Soc, vol. xi. N. S. p. 16.) 



The variation in size, form and number of striaj is very considerable in all 

 of these species from different localities, and for the reason this measures T 

 have given above are only approximate. 



As opportunity offers, I hope to continue the notice of the Delaware river, 

 and adjacent coastal diatoms. 



Plate II. 



Fig. (1.) Odontidium tabellaria. Sporangial varieties of primary form, (a), 



ordinary form, /? and y, elongated frustules. 

 (2.) Odontidium tabellaria. Sporangial varieties of secondary form. (6), punc- 

 tate variety of, c. elongated form, d. double sporangial frustule. 

 (3.) Telracyclus? (abnormal) a. V. b. F. V. 

 (4.) Eunotia pentaglyphis, (Ehr.) 



(5.) Navicula serians, a. (apiculale), b. (cruciform) variety=2V r . follii. 

 (6.) Stauroneis Stodderii, n. sp. (Greenleaf). 

 (7.) Navicula placenta, Ehr. 

 (8.) Navicula Sillimanorum, Ehr. 

 (9.) Navicula (Stauroneiform,) n. sp. ? 

 (10.) Navicula rhomboides. Sporangial var. b. 

 (11.) Navicula rhomboides, Sporangial var. a. 

 (12.) Eunotia incisa. (a) extreme variety, (Synedroid), b. Biundulate variety 



= Eu. camelus. 

 (13.) Himantidium undulatum. Sporangial, var. a and b. 

 (14.) Stauroneis legumen, Ehr. 

 (15.) Mastogloia Kinsmanii, n. sp. a. V. b. F. V. 

 (16.) Mastoglia elegans, n. sp. F. V. 

 (17.) Navicula gaslrum, Ehr. 

 (18.) Eunotia bactriana, Ehr. 

 (19.) Navicula interposita, n. sp. 

 (20.) Navicula incomperta, n. sp. 

 (15.) Navicula carassius, Ehr. 



These figures are all magnified 500 diameters. The representations of striae 

 are only designed to give a. general idea of their direction and character, not of 

 aumber, actual or comparative. 



[Jan. 



