On a New Species of Octopus. 319 



XXXI. On a Nev: Si^ecies of Octopus (0. maculosus). By 

 W. E. HoYLE, Esq., M.A. (Oxon.), M.RC.S., F.K.S.E., 

 Naturalist to the "Challenger" Commission. [Com- 

 municated by F. E. Beddard, Esq., M.A. (Oxon.), 

 F.E.S.E.]. [Plate VI.]. 



(Read 21st March 1883.) 



The specimen upon which the following description is based 

 was placed in my hands, with a label, bearing the single word 

 "Australia," and this is all the information I have hitherto been 

 able to procure with respect to its habitat : — 



Desckiption of the Specimen. 



Dimensions. 



Totallength, . . . . . 10 cm. 



Length of the body, . . , . 2 75,, 



Lengths of the arms. 



Left. Riglit. 



1st. . . . . 5 "75 cm. 6 cm. 



2d. .... 4-5 „ 5-75 „ 



3d. . . . . 5-75 ,, 6 . ,, 



4th. . . . . 6-5 ,, 7 ,, 



Breadth of the interbrachial membrane, . . 1'5 ,, 

 The lengths of the arms and the breadth of the interbrachial membrane are 

 measured from the margin of the oral aperture. 



The Body (PL VI., Figs. 1, 2) is subglobular, smooth, 

 quite devoid of cirri or tubercles, the mantle-opening reach- 

 ing about one-third round its circumference. 



The Head is small, not very definitely marked off from the 

 body ; eyes rather prominent. 



The Arms are subcorneal, of medium unequal length, their 

 order in this respect being 4, 1 = 3, 2.* They are armed with 

 small suckers, the innermost three or four being arranged in 

 a single row ; the suckers are so deeply imbedded in the sub- 



* Since this paper was read I have ascertained that there are four specimens, 

 apparently referable to the same species as the one here described, in the 

 Liverpool Free Public Museum, and Professor Herdman has been good enou-^h 

 to send me the following note on the relative lengths of their arms : 



A. 3, 4, 2, 1 on one side of the body ; 4, 2, 1, 3 on the other. 



B. 3, 4, 2, 1 on both sides. 



C. Arms much curled and stiff ; probably 3, 4, 2, 1 on both sides. 



D. 2, 3, 1, 4 on one side ; arms too much curled on the other to make out 



Avith certainty. 

 From this it would appear that the formula is 3, 4, 2, 1, but extremely liabh- 

 to variation. 



