NATURAL SCIENCES OP PHILADELPHIA. 67 



26. Navicula convex a W. Smith. Hab. New London harbor mud. Rare. 



27. Navicula humerosa Brebisson. Hab. Saguenay river, on algse. 

 Long Beach, N. J., on algse. L. I. Sound, algae. Common. 



28. Navicula Hennedyi W. Smith. Hab. Delaware river, Kaighn's 

 Point. Blue clay, fossil, Delaware river. New London, Conn., harbor mud. 



29. Navicula trochus Ehr. Hab. Blue clay, fossil, Delaware river. 

 Very rare. 



30. Navicula truncata Donlcin. Hab. Long Beach, N. J. New Lon- 

 don, L. I. ; algse, &c. 



31. Navicula minutula W. Smith. Hab. Brackish marshes at Absecom 

 Inlet, N. J. Cape May, salt marsh. Not uncommon. 



Differs in habitat and shape, which is more pointedly elliptic, but agrees in 

 striation and all other respects with the figure in Smith's Synopsis. 



32. Pinnularia long a Gregory. Hab. Providence, Fall river, on algae. 

 Newport, R. I., on algae. Rare. 



33. Pinnularia polyonca Brebisson. Hab. Very general along the coastal 

 ponds and rivers. Northam's Pond, along with Navicula trinodis. Ogee- 

 chee and Savannah rivers, on algae. Delaware river. On mud from Cooper's 

 creek, N. J., and Duck creek, Del. Our native variety often attains a length 

 of "005. The figure in Mic. Journ., vol. 2, pi. iv., conveying a very poor idea 

 of the size and general characters of P. polyonca, a representation of a 

 full sized specimen will be found in PL II. f. 7. 



34. Pleurosigma macrum W. Smith. Hab. Brackish marshes at Wil- 

 mington, Del., Mr. Febiger. Rare. 



- 35. Pleurosigma o b s c u r u m W. Smith. Hab Brackish marshes at Dela- 

 ware City, Port Penn. Marshes of Delaware City, Mr. Febiger. Rare. 



36. Pleurosigma intermedium W. Smith. Hab. New Rochelle, on 

 algae. Dredged from sea at New London. Very abundant in this locality, but 

 not elsewhere. 



37. Pleurosigma rigidum W. Smith. Hab. New Rochelle, on algae; 

 along with Pleurosigma intermedium at New London. Rare. 



38. Pleurosigma delicatiilum W. Smith. Hab. Delaware river. Rare. 



39. Licmophora splendida Ehr. Hab. Rocks off Newport harbor, on 

 algae, Mr. Powel. Common. 



40. Podosphenia Baileyi, n. sp., Edwards. F. V. Broadly cuneate, trun- 

 cate, sessile end often produced. V. Obovate, or suborbicular ; the lower ex- 

 tremity prolonged into a very acute point, striated ; striae about 55 in *001. 



Hab. Long Island Sound, on -algae. At Stonington. New London. Black 

 rock, Long Beach, N. J., on algae. Common. PI. II. f. 8. 



This is possibly the species alluded to by Mr. Edwards, in his paper on 

 American Diatomaceae, Mic. Journ., although in my specimens the presence of 

 vittae is sufficiently obvious. In this early stage the frustules are imperfctly 

 silicious and possess short stipes, but as the growth of the individual pro- 

 gresses these become absorbed, until finally, as in others of the genus, they 

 appear simply sessile. 



Since writing the above, my friend Mr. Edwards has informed me of the 

 identity of this species with his P. Baileyi, (manuscript.) 



41. Gomphonema m a r i n u m . Hab. New Haven harbor mud. Bannister's 

 creek, Rockaway mud, and New Rochelle, on algae. Not uncommon. 



1861.] 



