140 Transactions. 



South Island (G. M. Thomson) ; 1900. (c.) Tauranga, on the 

 east coast of the North Island (which is without date, and was 

 collected during my predecessor's time). 



The lot (a) include forms varying in size from 27 mm. to 

 62 mm. in length ; the largest I take to be adults. The lots 

 (&) and (c) are quite young, attaining a length of 9 mm., 6 mm., 

 and even less. They exhibit a series of stages of growth corre- 

 sponding to some of those figured and described by Agassi z* 

 for B. roseola, on pp. 36, 37. 



The youngest of my specimens has costae extending only 

 a short way down the body (c/. fig. 52 of Agassiz) ; the meridional 

 canals are relatively wide, have no branches, and open below 

 into a semicircular canal {cj. figs. 57 and 58 of Agassiz) ; but 

 in the former figure no marginal canal has appeared, while in 

 the latter there are already indications of coeca which are absent 

 in my specimens. 



In the lot (a), even in the smallest, the meridional canals are 

 provided with branched coeca, though the branches in the 

 smaller individuals (20-25 mm. in length) are not so much 

 ramified as in the older. (This measurement was taken after 

 transference from formol to alcohol, in which the specimens 

 shrink somewhat — losing about 20 per cent, of their former 

 size). In all of them the costse extend more than half-way 

 down. 



Remarks. — The question arises, Is a new specific name 

 required for this form ? Chun (p. 306) has pointed out in his 

 memoir the immense amount of synonymy — both generic and 

 specific — that occurs in the family BeroidfB, and comes to the 

 conclusion that, at any rate in the Northern Hemisphere, not 

 more than three species exist — namely, Beroe ovata, B. forskalii, 

 and B. cucumis. But he acknowledges that the forms that have 

 been gathered in the Pacific Ocean, and figured by older authors, 

 are insufficiently described to enable him to decide as to their 

 validity or otherwise. 



More recently, a species B. australis has been described by 

 Agassiz and Mayerf from Fiji, which, however, is quite dis- 

 tinct from the present form, and appears nearly related to B. 

 forskalii. 



But from each of the three species from the Northern Hemi- 

 sphere the present one differs in the following points : From 

 B. forskalii in form and sundry details which serve to distin- 



* Agassiz, N. American Acalephse, 111. Catal. Mus. Harvard, 1865. 

 f Agassiz and Mayer, " The Acalephs of Fiji," Bull. Mus. Harvard, 32. 

 1899, p. 177. 



