526 Proceedings of the Royal Irish Academy. 



acters of the included species are in many cases so ill-defined as to 

 render identification very difficult. 



[^Margelis Iritannica, Forbes {= Medusa duodecilia, Dalyell), was 

 common in June, 1885, at Kingstown and Dalkey. L. Agassiz (1862) 

 and Hseckel (1879) refer Bougainvillea Iritannica, Forbes, to the 

 genus Margelis, but AUman (1872) retains the genus. There is 

 sufficient evidence that this is the medusoid form of Eudendinum 

 ramosum, van. Beneden (1844), (the B. ramosa of Allman's Mono- 

 graph). According to the strict law of priority, Forbes' species 

 (described as Sippocrejie hritannica in 1841) has precedence of van 

 Beneden' s, but both AUman and Hseckel agree in adopting the latter 

 zoologist's name: Allman does so "in the absence of absolute proof of 

 this specific identity ; " Hseckel gives no reason. The alteration of 

 the specific name merely depends upon the identity of the two forms 

 in question, and since this is no longer doubted it is clearly our duty 

 to accept the less appropriate specific name of Forbes. Agassiz's 

 generic name, Margelis, will be provisionally adopted. The remarkable 

 inedMsaDipleurosoma hemispJierica, Allm., with its irregular gastrovascu- 

 lar canals and generative glands, was very common on June 27th, 1885, 

 at Kingstown. Allman first described it in Nature, vol. ix., 1873, p. 73. 

 as Ametrangia hemispherica (nov. gen. et spec), from the south coast of 

 Ireland. Hseckel, on p. 636 of hisMonograj)h oftheMedusce, relegates this 

 medusa to what is possibly its correct genus, and very character- 

 istically changes the specific name to B. irregulare, Hfeck., without 

 stating any reason for so doing. It is true that Allman's name is not 

 particularly well chosen, as there is a Thaumantias of the same name, 

 but the rules of priority of nomenclature can not be set aside solely to 

 introduce a more diagnostic term. Hseckel states he also met with 

 this medusa in the spring of 1879, in the neighbourhood of Portobello, 

 Brighton (Sussex). The present is the third record of its capture.] 



Strangely enough, I have only seen Aurelia aurita, Lion., in July, 

 1881, in Kingstown Harboiu- [and Rhizostoma octopus, Linn. (=i2. 

 pulmo, Forbes, not of Linn.) ; at Dalkey in June, 1885 : one specimen 

 of the latter must have been two feet six inches in length, and pro- 

 portionately broad.] 



Only on one occasion, and that was in Dalkey Sound, in September, 

 1883, did I come across a siphonophore. The specimen was very small, 

 i^ths inch in length, and was too immature to be identified with any- 

 thing like certainty ; I doubtfully refer it to Agahnopsis sarsii, Koll. 

 In the Natural History Review, vol. iii., 1856, p. 76, pi. vi. figs. 3, 

 4; and pi. vii. fig. 1, is an account of a siphonophore named Stepha- 

 nomia contorta, M. Edw., two specimens of which were found 

 by Prof. J. E,. Greene, on June 2, 1856, in Kingstown Harbour, 

 in a calm sea, during hot sultry weather. At the same time was 

 published a notice of Agahna gettyana, Hyndman, which was seen by 

 Mr. Edmund Getty in great numbers in Belfast Bay, ia August, 1841, 

 and also in July, 1852, by Mr. Hyndman, in great abundance in the 



