On the Cohoptero^is Fauna of the Cape-Verde Islands. 245 



Fi(j. 10. EvacuatoJ antheridiiim of the same species. A special mother 

 crll Ims rt'iuiiiniMl bi'liiiitl in tlic imi(>r spaoo. 



Fi<j. 11. Itiuliinculary aiithi'i-idiiiiu ol' Asplcniuiit tildtiaii. Only the lower 

 viiiLr (•'■U i^ cut oil'. Its coll-nuclous lay to the left, and wa3 

 distinct when the antheridiuni was g'enerallv in focus. 



Ti(/. 12. Like the last. 



Ft'//. 1']. Somewhat later devi'lopniental state. TIk; upper cell has divided 

 into a shallow bell-sluiped outer cell and the central cell : a Si b 

 as under fif^. 2. 



Fit/. 14. Tlie bell-shaped cell has already been divided into the second 

 ring cell and the opercular cell; the central cell is still undi- 

 vided. (After treatment with caustic potash and muriatic acid.) 



Fit/. L5. A somewhat older stage. Tlie central cell is already divided 

 into eight cells, of which only four are visible. (Treatment as 

 under fig. 14.) 



Fi//. 10. ^lature antheridium jwith three ring cells ; the intermediate 

 ring cell is set obliquely ujion the inferior one, so that one side 

 of the latter is excluded from the envelope of the special mother 

 cells. 



Fu/. 17. Evacuated antheridium, with three ring cells, in each of which 

 a spherical nucleus is distinctly visible. 



Fiff. 18. Young antheridium of Cibotiuin Schuhi, seen from above. Tho 

 central cell is broken up into four quadrants, of which two are 

 already again divided ; the operculum consists of two cells. 

 (After treatment with caustic potash and muriatic acid.) 



Fiff. 19. Young antheridium, seen from the side. The central cell is still 

 undivided. 15y a mistake of the lithographer, the circle in 

 which the lower funnel-shaped septum applies itself to the 

 outer wall is placed rather too low down. 



All the figures are drawn with the camera, and magnified ;323 diameters. 



XXY. — On Additions to the Cohoj^tcrous Fauna of the Cape- 

 Verde Islands, By T. Vernon Wollaston, M.A., F.L.S. 



Fam. HydropMlidae. 



Genus PiiiLiiYDRUS (Col. Hesp. p. 44). 



My attention has lately been drawn by Dr. Sharp (who has 

 studied the PhiUiydri with considerable care) to the tact that 

 Avliat I had hitherto regarded (on the authority, originally, of 

 Aubi') as the mclanocejdtalus of Olivier is not referable, in 

 reality, to tliat insect. Moreover the Ckqje-Verde examples 

 a]>pear, in addition, to be separable into two species, both of 

 Avhieh arc distinct from the one (recorded by myself, equally, 

 as the " meJanocephaJ as'''') which is so imiversal in the ^ladeiran 

 and Canarian archipelagos, and Avhieli Dr. Sharp is of opinion 

 should be identihed with the Mediterranean P. politus of 

 Kiister. These two Cape -Verde Fhilhi/dri he considered to 

 be undescribed ; and he has lately, therefore, at my own re- 

 quest, published diagnoses of them, which, iiowever, much 

 they may be related inter se, establish at all events the fact of 



