176 THE VOYAGE OF H.M.S. CHALLENGEK. 



genus Gonatus, not, however, without making several mistakes, which have since led to 

 great confusion. Steenstrup has tabulated the most serious of these as follows : — 



a. Gray overlooked the difference between the armature of the ventral and of the 

 other arms, not seeing the tips of the hooks in the two median series of 

 suckers, as his description "all with small circular rings''^ proves; the 

 same error reappears in the phrase " and the outer series of the cups on 

 the shorter arms are Hke the other, with circular arms and no hooks." ^ 

 M0ller had rightly observed that the horny rings had often a very small hook 

 on the margin, but thought, wrongly, that they had fallen out or were lost in 

 those cases in which he did not see them ("uncinis marginalibus minutissimis 

 et admodum caducis [rarissime obviis] instructis ").^ 



h. Gray denied the presence of the minute suckers along the stems of the tentacles 

 which M0ller had correctly observed and recorded ("brachiis pedunculatis 

 per totam longitudinem cotylis prseditis "), whilst Gray in his turn perceived 

 the hooks in the tentacular clubs whose existence M0ller regarded as 

 doubtful. (" Uncinos in brachiis ped. nondum vidi ; fortasse tamen adsunt, 

 sed seque caduci ac uneini brachiorum sessilium.") 



c. Gray states that the siphon has " no interior valve," and that it is " without 



superior central band " ; and 



d. That the giadius has no terminal cup, although in other respects his description 



of it is correct. 



Nothing was added to our knowledge of this form between 1849 and 1878, when 

 Professor G. 0. Sars published* some figures and a description of a small specimen 

 captured in the Porsangerfjord, concerning which Steenstrup makes the following 

 criticisms :^— 



" In the enlarged details of portions of an arm, and of suckers from the median and 

 lateral series, any one who is acquainted with Gonatus will readily recognise its 

 characters, and will also see in fig. 10 an approximate though not quite accurate 

 representation of its tentacles. The same holds of fig. 11, which represents the most 

 important middle portion of a tentacular club, except that the connective apparatus is 

 omitted both in the drawing'' and in the text. As regards the giadius, the ventral 

 aspect of which is shown in fig. 4, its terminal cone has been laid open in the middle 

 line and spread out on either side, instead of being retained in its proper conical shape 

 with which agrees also the expression in the text 'extremitate postico leviter 

 cochleariformi.' 



1 B. M. C, p. 67. 2 Op. cit, p. 68. 3 i^d. MoU. grcenl., p. 3. 



^ Moll. Reg. Arct. Norv., p. 336, tab. xxxi. 6 Op. cit, p. 14. 



" There are a number of minute dots along the arm which seem to me as though intended to suggest the presence 

 of minute suckers. — W. E. H. 



