1 10 o ( TOITS. 



that will even permit me to retain as distinct, many of the species 

 which have acquired :i certain authenticity from frequent 

 description, illustration or quotation; and rather than run the 

 risk of still further complicating the study by drawing con- 

 clusions from inadequate material, I prefer to adopt the imperfect 

 and erroneous sub-divisions of Gray and d'Orbigny, and simply 

 correct the synonymy of the species in cases where the evidence 

 lias appeared to me to be conclusive. 



Prof. Steenstrup (Ann. Mag. N. Hist., 2 ser. xx. 1x57) beli. 

 that the development of larger suckers upon the lateral arms is a 

 character belonging to the males only, and that it is found even 

 on some of the common species, like 0. vulgaris, which Gray 

 has placed in group 1. Thus, says Steenstrup, the male of 0. 

 t'ulyaris would belong to group 3, whilst the female would go 

 into group 1, and the same would be the case, according to his 

 observation, with 0. oculatux. Orb. 0. Fontanianus, Orb., the 

 principal species of this 3d group, is supposed by Prof. S. to be 

 an assemblage of males of several species. I have every reason 

 to believe that Prof. Steenstrup is correct, but I have not enough 

 material to decide whether the various " species " of Octopus 

 should be reduced to one, or six or sixteen. I am compelled to 

 retain Gray's classification, although it is worthless, arid to 

 describe fifty species almost without specific characters. 



Naturalists have lost that faith in the "immutability of 

 species," which formerly stood them in good stead of the so 

 much more difficult, extended and careful observation of develop- 

 ment, intimate organization and habits upon which the " species " 

 of the future must rest ; and unfortunately, the demonstration 

 which is to supplant our already lost faith, is in most cases, not 

 yet made'. 



Keferstein, in Bronn's " Klassen und Ordnungen des Thier- 

 reichs," (III, 1307-13]'.) and 141:5-1 1:21 ) gives an excellent resume 

 of the systematic history of the Cephalopoda, together with a 

 copious bibliography ; to which those curious in such matters are 

 respectfully referred, as it is foreign to the purposes of this work 

 to encumber its pages by detailing the steps by which con- 

 cliologists have attained their present, status of acquaintance 

 with the organization and relations of the mollusca. For a 

 similar reason, citations of authorities are avoided as much as 



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