120 Scientific Proceedings, Royal Dublin Society. 



similar to those of the specimens of this species which I have seen 

 both in Devonshire and at Dalkey Island. 



The third point in which my description differs with that 

 given by Grosse of both these forms raises considerations of much 

 greater importance. Gosse seems to have thought (Actin. Brit., 

 p. 4) that in all the sea-anemones, except Actinoloba (Actin. Brit., 

 p. 11) and Peachia (Actin. Brit., p. 234), there are always present 

 two oesophageal grooves. In the case of the genus Sagartia, he 

 definitely states (Actin. Brit., p. 25) that the mouth is " furnished 

 with two gonidial grooves, each with its pair of tubercles." Hollard 

 had previously (Annales des Sciences Naturelles, Zoologie, 3 ser., 

 t. xv., p. 274), and the brothers Oscar and Eichard Hertwig, 

 have subsequently (die Actinien, p. 57) stated that two oesophageal 

 grooves are to be found in all sea-anemones. In his Report on 

 the Actiniaria dredged by H. M. S. " Challenger" (p. 10), Professor 

 Richard Hertwig lays great stress on the existence of the two 

 oesophageal grooves, which he states are found in all Actiniae 

 except the Zoanthese and the Ilyanthidse, the former of which (he 

 states) have only one groove, and the latter none worth mention- 

 ing. Thus it seems to have been, on all hands, an admitted fact, 

 that with the exception, possibly, of Actinoloba dianthus, 1 and the 

 two families mentioned by Professor Richard Hertwig, all Actiniae 

 are characterized by the possession of two oesophageal grooves. 



I believe that this is not so, and that in the case of Sagartia 

 miniata, S. venusta, and S. nivea, specimens may frequently be met 

 with in which there is present only one groove. Last June I 

 found several specimens of S. miniata and S. venusta at Dalkey 

 Island ; all the specimens of 8. miniata had two grooves, and all 

 the specimens of 8. venusta only one. Subsequently Professor 

 Haddon sent me two more 8. venusta, from Valentia, and they 

 also had but one groove. A transverse section was cut off one of 

 these, and it exhibited but a single pair of directive mesenteries, 

 and they correspond in position with the groove. 



At the end of last December I made another visit to Dalkey 

 Island, and secured one specimen of 8. nivea, and several examples 

 of S. miniata and 8. venusta. The specimen of 8. nivea proved to 



1 As to whether Actinoloba dianthus invariably has two oesophageal grooves, see 

 F. J. Foot, 1861 : Proceedings, Natural History Society of Dublin, vol. iii., p. 64. 



