Hl FESTSKRIFT FÖR LILLJEBORG is 



of them certainly are; — e. g., the open eyes \ But, on the other hand, there arc se- 

 veral others which have more similarity with the corresponding ones of the Myopsids. 

 Such are, for instance, the single (left) oviduct and the presence of accessory nida- 

 mcntal glands. This seems to point out a specialisation to which the ancestors of 

 the OEgopsids had not come. Another strong resemblance to the Sepia- Loligo-group 

 of the Myopsids is the hcctocotylisation of one of the ventral arms, namely the left one. 

 It is true that Owen has shown- that in the male Spirilla ausiralis both ventral arms 

 arc modified, but it is the left one that is enlarged and it is probably effective during 

 copulation. This is too much to be merely a coincidence or a parallelism, the more 

 so as Steenstrup has proved that in all forms belonging to the same natural group 

 the hcctocotylisation always affects the same pair of arms. Supporting his opinion 

 with the situation of the hectocotylised arm in Spirula Steenstrup classed this Ceph- 

 alopode with the S^'a-family. This connection seemed at first completely cut off 

 when it was proved that Spirula had open eyes and thus was an "OEgopsid". But 

 although the affinity cannot be so close as Steenstrup believed when he regarded 

 Spirula as a "Myopsid", we may nevertheless assume that there was an earlier relation 

 between the ancestors of Spirula and the ancestors of Scpiida:, for these must have 

 developed from forms with open eyes and external shells. These common ancestors 

 must have had a single (left) oviduct, accessory nidamental glands and hectocotylised 3 

 ventral arms 4 etc. contrasting with the forms probably Belemnite-like in character 

 which were the progenitors of Onychotenthidce and Ommatostrephidce and had two 

 oviducts and no accessory nidamental glands etc. 



The Spiriilirostra of the Tertiary is now by some scientists (e. g. Zittel) 

 joined with Spirula into one family and regarded as a Spirula which has acquired a 



1 Primitive is also according to Pelseneer himself (1. c. p. 23) the character of the "posterior 

 aorta with recurrent branch (genital)". 



2 Proc. Zool. Soc. 1880 Part II p. 352 — 4, PI. XXXII. 



1 The hectocotylised arms are in Spirula ai/stra/is, as in Idiosepius pygmmts Steenstrup, completely 

 deprived of suckers. 



4 Although the Ommatostrephida and Onyehoteuthida have the ventral arms hectocotylised there 

 exists a great biological difference between these two OEgopsidfamilies and the Sepia-Loligo family because 

 in the former the spermatophores are fixed by the copulating male on the inner side of the mantle in the 

 pallia] cavity, whereas in the latter, on the inner side of the ventral portion of the buccal membrane. In 

 Spirula no spermatophores have been found as yet, but the great development of the ventral part of the 

 buccal membrane in our specimen makes it more than probable that this is the place for the spermatophores 

 in Spirula too. (It is possible that the spermatophores have been washed away). Therefore I believe we 

 may find in this a biological character which Spirula and Sepia-Loligo have in common. I cannot omit to 

 call attention to the striking resemblance in regard to the development of the ventral part of the buccal 

 membrane in Spirula and in Idiosepius pygmaws Steenstrup (conf. Tab. I. K. Dansk, vidensk. Selsk. Skrifter 

 6 Raelcke, Kjöbenhavn 1881). 



