194 Transactions of the Royal Canadian Institute 



dorsum not so distinctly marked off from the sides of the body; lastly 

 the dorsal appendages are entirely different. In Tethys they number 

 about 13 pairs, are small, alternate in size and are somewhat tufted. In 

 Chioraera the appendages, relatively much larger, are 10 in number, do 

 not alternate in size and are perfectly plain. For these reasons I have 

 placed Chioraera in the family Tethymelibidae of Eliot to indicate its 

 similarity to Tethys and Melibe and also constituted for it a separate 

 genus Chioraeridae to call attention to the noticeable differences betwefein 

 it and the other genera. I find myself unable to accept the classifica- 

 tion of Bergh (3a) who places it in the genus Melibe. It is hoped to 

 establish its relationship more securely later by further more detailed 

 study of its anatomy. 



Habitat. — There seems little doubt that this species is mainly pelagic 

 for it is found floating freely in the sea during the early months of the 

 year and I have seen it at the end of July and middle of August. Towards 

 the middle or end of May however it comes in to spawn and it is then 

 very plentiful. One spawning place is the Zostera bed round the Station 

 float and another is on a similar bed on Mudge Island. Apparently it 

 comes to the former a week or so earlier than the latter. At this time 

 the animal is present in hundreds and so constitutes an extremely common 

 form at these two points. Even then however it does not creep about on 

 the eel grass but only seems to adhere for the purpose of laying its eggs. 

 In the laboratory too it does not creep on the sides of the aquaria and 

 only rarely clings to them. It has not been observed creeping on anything 

 after the manner of othei Nudibranchs and if not entirely a pelagic form 

 like Phyllirhoe it is beyond doubt very nearly so and is a most interesting 

 form. 



Family Aeolididae. 



Limaciform animals bearing unbranched cerata on the dorsal surface. 

 The liVer is represented by the diverticula which these cerata contain, 

 and does not, as in Dendronotidae, etc., form masses in the body cavity. 

 Rhinophores simple or perfoliate, but never with sheaths. Radula 

 uniseriate or triseriate. Cnidocysts usually present. 



a Triseriatae. 



Each transverse row of the radula contains three teeth. 



Genus Coryphella (Gray). 



Coryphella Bergh, Malakol. zool. Blatter, II, 1875, etc. Alder and Han- 

 cock, Monog. Brit. Nudibr. Moll., Pt. VII, 1855, p. 49. Vayssiere 

 Anal. Musee d'Hist. Nat. de Marseille. Zool., Vol. Ill, 1866-1889. 



