36 THE OCEANIC HYDROZOA. 



in his species is open. I believe, however, he has overlooked the anterior wall of its 

 hydrcecial canal. If he has not, then B. acuminata is not D. Sieholdii, in which Kolliker has 

 not only described (p. 38), but has figured (tab. xi, fig. 8), the wall in question. Leuckart 

 also admits the great similarity of his D. acuminata with D. Sieholdii, but says that his 

 species is " distinguished by the presence of a closed canal for the passage of the ccenosarc 

 (Durchlass-kanal) in the posterior swimming organ." However, this is contrary, as we see, 

 to Kolliker's express statement. 



Under the head of Eudoxia Lessonii [infra) will be found my reasons for believing that 

 form to be the free Diphyozooid of D. appendiculata. 



DiPHYES Chamissonis (u. sp.) PI. I, fig. 3. 



The proximal nectocalyx is very wide above, where it ends in an obtuse point. The 

 anterior and posterior contours are nearly parallel ; the posterior is straight ; the anterior, a 

 little convex. The anterior ridges are serrated, and produced below into three strong incurved 

 points. The nectosac is wider superiorly than at the mouth, and ends above, close to the 

 apex of the organ, in an obtusely pointed dome. 



The hydroecium has about half the length of the nectocalyx, and is straight, conical, and 

 widely open below ; its anterior wall is a single plate, deeply emarginate below, and somewhat 

 convex forwards ; the posterior wall is also emarginate ; and the inferior edges of the lateral 

 walls are but very slightly oblique. 



The somatocyst is subcylindrical, and not so long as the hydroecium. 



The hydrophyllia resemble those of Diphi/es dispar. 



I took the detached proximal nectocalyces, with the ccenosarc attached, of this species, 

 repeatedly, on the east coast of Australia and in the Louisiade Archipelago, during the years 

 1847, 1848, and 1849 ; but I was never able to obtain the inferior nectocalyx. 



The specimen figured was about half an inch long ; the fully formed hydrophyllia measured 

 one twelfth of an inch. 



I am unable to identify this with any of the described species of Biphyes. 



DlPHYES MITRA, n. Sp. (? APPENDICULATA). PI. I, fig. 4. 



The proxjmal nectocalyx is considerably wider above than below ; and is obtusely 

 pointed at its apex. The ridges of the anterior face are serrated, and end below in almost 

 obsolete points. The hydroecium attains hardly more than one fourth of the length of the 

 organ ; it is obtusely conical, with a slightly recurved apex, beneath and in front of which 

 arises the narrow neck of the somatocyst; the latter hardly extends beyond the middle 

 of the length of the nectosac, and its walls are not vacuolated. The anterior wall of the 

 hydroecium is formed below by two triangular plates, which extend inwards from its lateral 

 walls, and overlap one another throughout their superior halves. 



Hydrophyllium a very thin plate, whose edges are bent upon themselves, but do not 

 completely overlap ; the middle part of the inferior margin produced into a lobe. 



