12 SIR CHARLES ELIOT 



branchial or tentacular appendages at one extremity of the body. Similarly, Elysiadae 

 and Planarians are much alike in form, and constantly mistaken for one another ; both 

 are thin sheets of living matter, which progress by creeping and swimming. 



Notaeolidia, gen. nov. 



This new genus seems worthy to form the type of a new family intermediate 

 between the Aeolididae and such forms as Dendronotus and Lomanotus. Externally 

 the animals resemble the Aeolids, and are chiefly remarkable for their great size. They 

 have no frontal veil, but large oral tentacles, perfoliated rhiuophores without sheaths, 

 and numerous cerata, arranged somewhat as in Gonieolis. The internal digestive 

 organs, however, deviate from the type of Aeolis. The portion of the hepatic system 

 within the body cavity consists of a folliculate mass as well as of tubes, and lies under 

 the large hermaphrodite gland ; the radula consists of a few rows (generally eighteen), 

 each containing nine or sometimes eleven teeth. On the one hand, it is practically the 

 radula of Coryphella and Gonieolis enlarged and extended ; on the other, it presents 

 resemblances to that of Dendronotus on a small scale. 



Two or three species are known. N. gigas and N. purpurea described below are 

 perhaps only varieties of one form, and differ chiefly in size and colour. N. depressa, 

 obtained by the Discovery, which will be shortly described by me, is flatter, and super- 

 ficially resembles Lomanotus, as it has only a single row of cerata on the mantle margin. 

 It resembles N. gigas, however, in all essential points, and the radula is similar, though 

 specifically distinguishable, the laterals being narrower and the denticles larger. 



The characters of the genus, which are at present those of the family, are as 

 follows : 



Large animals of Aeolidiform appearance. Oral tentacles large : rhinophores per- 

 foliate without sheaths. Foot rounded and grooved in front. Dorsal margin un- 

 dulated, and bearing one or more rows of close set cerata. Jaws not denticulate. 

 Radula consisting of a central tooth and four (rarely five) laterals on each side. Central 

 tooth with strong median cusp and side denticles ; laterals denticulate on inner side. 

 The liver forms a lobed flocculent mass within the body cavity, and in the body walls 

 a thick spongy layer, from which rise the diverticula which enters the cerata. The 

 hermaphrodite gland lies above the liver. 



Notaeolidia gigas, geri. et spec. nov. 



The collection contains six specimens, which, though differing considerably in size 

 and somewhat in appearance, all seem referable to the same species. The largest (to 

 which the details given in the description below refer unless otherwise stated) is no 

 less than 122'5 mm. long. The measurements of the others are as follows : 



(ROY. soc. EDIX. TRANS., VOL. xi.i., ~>-2(i.) 



