"70 PROVISIONAL AID TO THE STUDY OF TASMANIAN MOLLUSCA. 



secreted ; cups slightly pcdicelled ; a pair of aquiferous 

 pores at the upper hinder angle of the eye. 



Genus. 

 Characters those of the family; the 

 third right arm of the male is 

 hectocotylised ; shell thin, trans- 

 lucent ; nautiliform, white, usually 

 two nodose keels at periphery Argonauta (3) 



Sub-Oedeb DECAPODA. 



Ten arms,o£ which eight are sessile, and two (longer) tentacular, 

 shell internal. 



(1.) Internal shell horny. 

 (a.) Eyes covered by sldn ; mostly littoral species. 



Family 

 Body long ; tentacular arms, partially 



retractile Loliginidse 



Body short ; tentacular arms, completely 



retractile Sepiolida3 



(5.) Eyes naked; Pelagic species. 

 Body long, cylindrical ; arms or tentacles 



armed with hooks Onychoteuthidse 



Body Jong, cylindrical; arms with suckers 



only Ommatostrephidse 



(2.) Internal shell calcareous. 



(a.) Shell blade li re Sepiidse 



(&.) Shell forming a series of chambers 



transversed by a siphon Spirulidas 



(iii.) Family Loliginid^. 



Body rather long ; buccal skin sometimes armed with 

 suckers ; tentacular arms only partially retractile ; fins 

 lateral, terminal ; inner shell or gladius as long as the 

 hack. (Calamary.) 



Body long, with posterior rhombic fins 

 united behind ; mantle supported 

 by a cervical ridge, a,r.d by cup-like 

 cartilages on the base of the 

 funnel or siphon ; siphon valved, 

 attached by bands to the head ; 

 arms with two rows of suckers, 

 provided -withhorny dental ed rings ; 

 tentacular arms with four rows of 

 suckers on their clubs ; fourth 



Genus. 



