st. Mollusca from Juan Fernandez. Addenda. 
By 
NILS HJ. ODHNER, 
Stockholm. 
Since the publication of my report on the mollusca of Juan Fernandez 
and Easter Island, forming No. 22 in the Series of Zoological papers edited 
by Prof. SKOTTSBERG, some additional material of cephalopods has been 
handed over to me for identification; it deserves to be published for completing 
the list of mollusca from this interesting tract. In the present note these 
species of cephalopoda are reported; they were collected by the same Swed- 
ish Pacific Expedition 1916—17 by Mr. K. BACKSTROM. In this connection 
it may be mentioned that in another paper I have dealt with some few forms 
from Masatierra collected during an earlier visit to Juan Fernandez by Prof. 
SKOTTSBERG, viz. in 1908.1 For the sake of completeness I give in this 
account a brief survey of the species recorded in that paper. One of them 
was described as new, viz. Marinula juanensis, and proved a close relation to 
a West American species of the genus Pedipes (P. unisulcatus from Mexico). 
The remaining mollusca reported were marine gastropoda of the following 
species: Helszoniscus ardosiaeus Hombr. & Jacq., Deloma nigerrima Gmel. and 
Littorina mauritiana Lam., the last recorded also in my first report. Dzloma 
nigervima was not previously known from Juan Fernandez. Also the two ce- 
phalopods mentioned below are accessional to its molluscan fauna. 
Octopus vulgaris Lamarck. 
One specimen (J) with a total length of 60 cm (whereof body and head 
10 cm) was captured at Masatierra the ?"/, 1917, another (2), 53 cm 
in length (whereof body and head 18 cm), was captured the '°/3 1917 at 
Masafuera. 
There is no doubt that these specimens belong to Octopus vulgaris Lam. 
They show the characteristic dermal warts, the 3 supraocular cirri and the 4 
dorsal ones arranged in a rhomb. The suckerless end of the hectocotylized 
arm is very short, equal in length to the adjacent part of the arm which bears 
1 N. Hy. Opuner, Marinula juanensis n. sp., nebst Bemerkungen tiber die Systematik der 
Ellobiiden. Arkiv f, Zoologi (K. Sv. Vet. Akad.), Bd 17 A, No. 6. 1925. 
