606 LÖNNBERG, NOTES ON SOME RARE CEPHALOPODS. 



25. The three upper pairs of arms seein to be more niuscular 

 than the ventral and carry two dense rows of suckers each. The 

 ventral arms are more slender than the others, iighter in colour, 

 and almost whiplike in shape, but delicately webhed. On their 

 proximal part alone, they carry (6) 8 minute suckers arranged 

 in one row and at a comparatively large distance, 2 — 4 mm.^ 

 from each other, with the exception of these they are quite 

 unarmed. It is evident that with such a structure the ventral 

 arms cannot have a predatory function, but are feelers. Mastigo- 

 teuthis agassizi Verrill has two rows of suckers »on all the 

 arms».' Our specimen is thus very much aberrant in this respect 

 although its ventral arms have the same shape as those of M. 

 agassizii. The suckers of the first three pairs of arms resemble 

 those of Mastig oteuthis agassizi except that the horny rings 

 have not an »entire margin» nor such pointed teeth as the Chal- 

 lenger specimen -) but are provided with broad truncate nearly 

 square-cut teeth all around the aperture. ^ This may also be a 

 character of specific value, The minute suckers of the ventral 

 arms have the same structure as the others. 



The eyes are large with thick glassy-looking eye-lids. 



The colour is reddish, due to very numerous and large, oval 

 chromatophores distributed all över the animal, except on the 

 ventral arms where they are scarce and small. 



The mantle seems to have a semi-gelatinous subcutaneous 

 layer. 



The »pen» or »gladius» is anteriorly and in its middle part 

 very slender with two yellow submedian costae and a thin 

 hyaline margin. Its posterior third is rather abruptly dilated and 

 the margins form a hollow conical portion with the free ventral 

 edges in contact with each other and strengthened by hyaline 

 thickenings, triangulär in section. The anterior part of the gla- 

 dius is not quite 1 mm, broad, while at its narrowest (middle) 



1) Verrill 1. c. p. 297. 



2) Challenger, Rep. Cephal. pl. XXIX iigs. 8—10. . 



^) Thus they partly resemble the same organs of Spirula reticulata. 



