196 Transactions of the Royal Canadian Institute 



off and its comers produced outwards into longish curved tentacles. 



Rhinophores. — -The rhinophores are long and non-retractile. They 

 lie at the front of the dorsum, anterior to the cerata and slightly median 

 to the continuation forward of their line. The perfoliate clavus occupies 

 more than half the length of the rhinophore and contains 32-38 shallow 

 leaves. 



Radula. — The pale radula is narrow and short and bears 19 rows of 

 teeth each composed of three teeth. The base of the median tooth is 

 somewhat horse shoe shaped. There is a long well developed sharply 

 pointed median point. On each side of the median spine are a series of 

 lateral denticles which are subject to a certain amount of variation; thus 

 while the most common number appears to be six on each side, teeth are 

 present with five only on each side, 4 on one side and 6 on the other or 

 even 7 on one side. The lateral teeth have an irregularly triangular 

 base with a long sharp lateral spine. On the inside of the base of this 

 spine are a series of denticles varying in number from 5-3, 4 or 5 being 

 the commonest number. 



Jaws. — ^The jaws are well developed, of an oval hollow shell shape 

 and yellow colour. The crista connectiva is fairly well developed and 

 the masticatory edge quite strong and brown in colour. The edge bears 

 a number of tiny slightly curved spine like denticles arranged in four or 

 five rows some considerably higher than the others. 



There is no doubt that this is the same form that Bergh (2) described 

 as Coryphella sp. from a single bulbus pharyngeus dredged in 9-16 sp. 

 fathoms off the Aleutian Islands. It agrees exactly with it in the form 

 of the radula and the jaws. It is also clear that not only in these points 

 but also in its general external appearance and internal anatomy it 

 corresponds quite closely with the typical members of the genus although 

 differing sufficiently to merit its being considered as a separate species. 

 In one point however it differs rather strikingly from other species of 

 the genus and that is the character of the rhinophore. Both Bergh and 

 Eliot state that a diagnostic character of the genus is the possession of a 

 smooth or wrinkled or at any rate a non perfoliate rhinophore. The 

 present species has undoubtedly got a perfoliate rhinophore with 32-38 

 distinct but moderately shallow leaves. So closely does it approximate 

 to other members of the genus that it does not appear justifiable to place 

 it in a new genus and consequently I have altered the diagnosis of the 

 genus to "rhinophores usually smooth or wrinkled but may be per- 

 foliate" in order to include it. It is here described under the name 

 Coryphella fusca. 



Habitat. — This species is not rare and appears to be the 

 commonest Aeolid in the neighbourhood. It has been dredged in from 



