DESCRIPTIONS OF GENERA AND SPECIES. 



Every one who, within the last few years, has attempted the task of identifying a 

 considerable collection of Cephalopoda must have felt great difficulty in deciding what 

 forms were to be regarded as new ; a result mainly owing to the brevity and insufficiency 

 of the published descriptions of a large proportion of the hitherto known species. Taking 

 warning by such experiences I have endeavoured to bequeath to my successors as little 

 trouble in this respect as may be, though I cannot hope that there will not come a time 

 when the diagnoses given below will be found inadequate to the requirements of the day. 

 I have endeavoured, without being unduly proUx, to make mention of every feature in 

 the appearance of the animal which could be of systematic significance, whether I have 

 myself thought it of much importance in that respect or not. 



The specimen has been invariably placed for descriptive purposes in a position, 

 indicated in the annexed woodcut (Fig. 1), which agrees with what may be called the 



DORSAL 



ANTER10R*l____^^K^|^^^gr" - TlPOSTERIOR 



VENTRAL 



Fig. 1. — Lateral view of a Seiyia, showing tlie position in which the specimen is placed for description. 



" morphological disposition " adopted by Lankester,^ if the inclination to the horizontal, 

 which is inconvenient for practical purposes, be neglected. In speaking of the arms, the 

 side which is turned towards the mouth and bears the suckers has been called the " inner " 

 and the opposite the " outer," and the same terms have been applied to the two surfaces of 

 the interbrachial membrane or " umbrella." " Breadth " has always been used to signify 

 a transverse measurement, and "length" a measurement parallel to the longitudinal axis 

 of the animal, although, as in the fins of Cirroteuthis, the former may greatly exceed the 

 latter. Several structures, to whose systematic value attention has been called by 

 Steenstrup, have been called by translations of his names ; thus " Hseftepuder " has been 

 rendered by "fixing cushions." Other names which have been adopted for the parts of 

 the shells of Sepia and for other structures will be explained as they arise. 



1 Ency. Brit., vol. xvi. p. 664, 1884. 



