270 Narrileal or Cochin Mud Bank. [No. 12, new series. 



moniliform, not quite reaching the median line, a smooth median 

 fascia continued into the marginal striae by four unequal wedge 

 shaped space 1 , two on each side, striae 21 in. 1.1000." 



Navicula (? Sp.) 



Broadly lanceolate, the extremities gradually contracted into 

 somewhat obtuse beaks, longitudinal striae strongly marked, 28 to 

 1.1000," Transverse striae rather obscure, requiring oblique illu- 

 mination, 32 to 1.1000"— length 1.120." This may be N. Indica 

 but the description* is too meagre for identification. 



Genus STAURONEIS (Ehr. K.) 



Stauroneis aspera (Ehr. Kutz.) 



S — (? Sp.) small, acutely rhomboidal, stauros narrow, 



reaching the margin, striae inconspicuous. Length 1.390." 

 Genus PLEUROSIGMA (Smith. Gyrosigma, Hassall.) 

 Pleurosigma iEstuarii ? (Breb. Sm.) 



p balticum (Ehr. Sm.) 



P intermedium? (Sm. 



p strigilis ? (Sm.) 



P inflatum (Shadbolt.) 



FAMILY XIX.— ACTINISCEJE. 



Genus DICTYOCHA (Ehr.) 

 Dictyocha Epiodon (Ehr.) 

 Genus MESOCENA, (Ehr.) 

 Mesocena octogona (Ehr.) 

 M binonaria (Ehr.) 



The foregoing list contains in all sixty-two species, belonging to 

 thirty Genera ; some of those I have described are probably new to 

 Science, but in the absence of authenticated specimens or even 

 drawings of, nearly all, the species foreign to Great Britain, I have 

 considered it prudent to leave them unnamed, and whenever I 

 have had any doubt of the identy of a species I have signified it 

 by adding a note of interrogation. 



It is probable that when I have had time to examime the larger 

 supply lately received, and for which I am indebted to the kind- 

 ness of Captain Castor, that the number of species will be at least 



* Note. — Of that species in Pritchard's Infusoria. 



