NUDIBRANCHS OF THE VANCOUVER REGION 205 



Dimensions. — ^The largest specimen measured when alive was 14 mm. 

 long by 2.75 mm. high and 2.25 mm. 



Head.— The head is not well marked off from the veil and is fairly 

 broad. It bears a small longitudinal slit-like mouth. 



Foot. — ^The foot is elongated and gradually gets narrower from the 

 abruptly rounded almost concave front end to the pointed tail. 



Rhinophores. — The rhinophores are non perfoliate and in the form of 

 blimt ended cylindrical rods. The part corresponding to the clavus is 

 slightly roughened but shows no signs of leaves. They are completely 

 retractile into prominent deep cup shaped sheaths with a smooth margin. 



Radula. — The radula is very pale and even taking into consideration 

 the small size of the creature very tiny being quite long and exceedingly 

 narrow. It is uniseriate and bears 86-96 rows of teeth. Each tooth has 

 a horse-shoe shaped base with a median spine and three small lateral 

 spines. The lateral spines are situated near the apex and two near the 

 base of the median spine. The two near the apex are asymmetrical 

 one being higher up than the one on the other side and this arrangement 

 is alternate. Thus if on one tooth the right one is nearer the apex than 

 on the next tooth it is the left one and so on. 



Jaws. — The jaws are fairly thin and very pale. They are oval in 

 shape and smooth, occupying the major part of the pharyngeal mass. 



The penis is short and conical and without armature. 



This form is undoubtedly a member of genus Doto and so is as far 

 as I can ascertain the first species of that genus to be recorded from the 

 Pacific coast of North America. It is quite distinctive and differs from 

 other species described elsewhere although it is nearly allied to Doto 

 coronata and so has been here described as a separate species under the 

 name Doto columbiana. 



Habitat. — ^Three specimens were dredged in July in from 12-18 

 fathoms between the end of Brandon Island and the head of Departure 

 Bay and two more in 15-20 fathoms in Nanoose Bay. They were all 

 brought in alive and kept so for some hours before preservation. 



Summary. 



In the foregoing list of Nudibranchiate Mollusca the following eight 

 are placed on record as new species : 



Triopha elioti, Acanthodoris nanaimoensis , Idalia vancouverensis , 

 Dendronotus giganteiis, Dendronotus rufus, Coryphella fusca, Coryphella 

 irilifieata, and Doto columbiana. Of these T. elioti and C. fusca have been 

 partially described but not named, by previous workers; in the former 

 case from badly preserved material and in the latter from a fragment 

 but in each case insufficiently to justify the author in naming them 



