o'mEARA ON NEW FORMS OF DIATOM ACEvE. 157 



with the general characters of this form ; but the hispid appearance of 

 the cellules, and their quadrangular figure at the base, entitle it to be re- 

 garded as a variety. 



Raphoneis suborhicularis. — Fig. 9, x 600; N. sp., O'M. Valves 

 nearly orbicular; length, -0022; breadth -0019; divided into com- 

 partments by short costae — eight on one side, nine on the other, alter- 

 nately disposed ; the spaces between the costae filled up by three lines 

 of puncta, the two outer lines receiving the central vacant space or 

 rhaphe ; the intermediate line much shorter. This species, in its ge- 

 neral characters, very much resembles a form figured by Grunow, and 

 with hesitation regarded by him as a variety of Cocconeis Grevillii. 



The absence of acentral line and central nodule, as well as the 

 presence of a distinct rhaphe, mark the present form as belonging to 

 the genus Rhaphoneis. The form figured by Grunow is narrow-ellip- 

 tical ; mine is nearly orbicular. These differences notwithstanding, I am 

 disposed to think that Grunow' s forms and mine are, at best, but va- 

 rieties of the same species. 



Rhaphoneis Jonesii. — Pig. 10, x 600; N". sp., O'M. Yalve broadly 

 elliptical; length, -0018; breadth, -0014; striae radiate, moniliform, 

 cellular, close, compressed, very large at the margin, and gradually 

 decreasing in size towards the rhaphe, which is narrow and el- 

 liptical. 



Rhaphoneis Moorei. — Fig. 11, x 600; N. sp., O'M. Yalve broadly 

 elliptical; length, -0016; breadth, -0011; striae radiate, moniliform; 

 cellules of the same size throughout ; rhaphe narrow. At first inspec- 

 tion of the figures it might appear that this form is identical with the 

 preceding; but, on consideration, the differences are so great as to 

 warrant me in regarding them as distinct species. 



The rhaphe in the former, though narrow, is wider than in the pre- 

 sent ; the former has a distinct border, this has none ; but the most 

 marked difference is to be found in the character of the striae. In the 

 case of R. Moorei the cellules which form the striae are all of nearly the 

 same size, round and distant ; whereas, in the case of R . Jonesii, the 

 cellules are so close as to give a costate appearance to the striae ; they 

 are also flattened, and decrease in size from the margin towards the 

 rhaphe. 



Rhaphoneis Areheri. — Pig. 12, x 600; N". sp., O'M. Yalve ellip- 

 tical ; striae slightly radiate, distinctly costate, distant ; rhaphe lanceo- 

 late. A form described by Grunow, and by him called Rhaphoneis scu- 

 telloides, so far as the figure is concerned, so closely resembles the 

 present, that at first I was disposed to regard mine as identical with 

 it, but from the description there is no doubt it is distinct. The striae 

 of R. scutelloides are described by Grunow as " indistincte punctatis;" 

 in R. Areheri they are distinctly costate. 



Mr. John Good exhibited some barnacles found attached to a frag- 

 ment of timber in the channel. He was disposed to regard them as of 

 foreign origin, and that they had propagated there during the time he 



vol. v. x 



