ZOOLOGICAL AND BOTANICAL ASSOCIATION. 119 



It is with very great pleasure I am permitted to call this species after 

 my friend the Rev. Eugene O'Meara, to whom I trust it may afford some 

 gratification to have his name associated with this species of a group 

 kindred to his favourite and beautiful Diatoniace©. 



There remains one other new species which it becomes my duty to 

 bring forward and describe, which, owing to its elongate form, and not 

 being at all constricted, and its entire segments, at once takes its place 

 in the genus Penium.* It is in size about equal to Penium Brihi&sonii, 

 but otherwise not at all resembling that species. Its outline is broadly 

 spindle-shaped or fusiform, tapering pretty quickly to the ends, with 

 cuneate segments, which are bluntly and roundly pointed, and it presents 

 always the same form when made to roll over. The endochrome is gra- 

 nular, and bright green, with a transverse, rather sharply defined, pale 

 band at the centre ; and usually has immersed in each half a single 

 central corpuscle. Close to each end there exists a smoothly and sharply 

 defined, perfectly circular cavity, excavated, as it were, out of the endo- 

 chrome, in which there are two or three active granules, as in Closterium 

 (see Fig. 14). The endochrome sometimes appears as disposed in longitu- 

 dinal fillets, but more frequently this is not evident The drawings repre- 

 sent this fully as marked as I have noticed it. The mode of division in this 

 form appears to follow that in Closterium, by a separation of the contents 

 and external constriction. Fig. 1 5 represents this process half accomplished. 

 I was not able to see its commencement, but in the specimen from which 

 the drawing has been taken, in about thirty-six hours from the time I 

 saw the stage represented in the figure (Fig. 15), the new halves were 

 completed. As is usual, the new segments maintained a connexion with 

 each other simply by the extremity, until they had nearly fully grown, 

 when they became detached ; but I could not see that they were held 

 together, or at all surrounded by any gelatinous investment. Like Pe- 

 nium Brihi%%onii and others, however, it may be that this is sometimes 

 absent, though at other times abundantly evident. I apprehend that 

 the act of division indicates that the individual had attained the full 



* The description of this species of Penium having been written since this paper was 

 read, and since the former part of it went to press, the " heading" includes only four new 

 species, instead of five ; but I have, nevertheless, introduced it, anxious to take advan- 

 tage of the Plate. 



