NUDIBRANCHS OF THE VANCOUVER REGION 1 93 



was body 58 mm. long by 28 mm. wide and 30 mm. high and the hood 

 varied from 18 mm. long by 26 mm. wide to 24 mm. long by 32 mm. wide. 

 The total length of the animal therefore was 82 mm., i.e., about 33<^ ins. 

 long. The first pair of dorsal cerata may project upwards as much as 

 23-24 mm. 



Head. — The large head itself is composed of two large pads which 

 together form a hemisphere with a deep longitudinal cleft, constituting 

 the mouth, between them. It is completely enclosed by the large velar 

 hood which as noted above is bilobed with a median notch in front and 

 constitutes when expanded about ^ of a hollow sphere the opening being 

 upon the ventral side. The inner margin of the opening is provided with 

 44-50 close set tentacles each from 5-6 mm. long and tapering to a point. 

 Within these again and close to them is another row of shorter, finer, 

 more numerous tentacles. The margin of the velum is strongly con- 

 tractile. 



Foot. — The foot is very narrow and long. It runs the whole length of 

 the body, is bluntly roimded anteriorly and a little sharper posteriorly. 

 At the front end it is about 5 mm. wide and at the back about 3 mm. 

 The edge of the foot forms a shallow flange marking it off sharply from 

 the side of the body. As a whole it is but feebly developed. 



Rhinophores. — No structures comparable with the rhinophores of 

 other nudibranches cpuld be found imless the cephalic appendages are 

 their modified representative, which hardly seems probable. 



Branchial cerata. — The first pair of appendages are practically 

 symmetrically placed but the remaining appendages alternate those on 

 the left side being slightly in front of those on the right. They diminish 

 quite rapidly in size so that the end ones are quite small. Although 

 large and inflated the leaves are attached by a very small area to the 

 body and are very easily shed even in life. It is difficult in a preserved 

 specimen to retain the full number. 



Radula. — The radula and jaws or any representatives of such struc- 

 tures are entirely absent. 



This species has been recorded by Gould (9), Cooper (5), and 

 Fewkes (8) from Puget Sound, Santa Barbara and Monterey but has 

 not yet been satisfactorily described or classified. It is an animal of a 

 most striking appearance and undoubtedly allied to Tethys and Melibe. 

 Both forms are provided with the same extraordinary cowl-like hood 

 over the head and probably capture their food in a similar way. Melibe 

 has a feebly developed pair of jaws whereas neither Tethys nor Chioraera 

 have any sign of them. In general shape these two latter forms resemble 

 one another fairly closely. There are however certain important differ- 

 ences. Chioraera has a relatively far narrower foot; it is higher and the 



