ATLANT. DEEP-SEA EXPED. 1910. VOL. III]. 



CEPHALOPODA. 



the dorsal side of the enormous fins. This is a structure 

 of the skin similar to the one observed by Joubin in an 

 Onychoteuthid and explained as a coating of scales. The 

 French scientist applied the name of Lepidoteuthis to this 

 large cephalopod, which was taken from the stomach of 

 a whale. I have previously stated (1910, p. 6), that 

 the structure in question is by no means a coating of 

 scales; it is a peculiar structure of the cuticle, which only 

 becomes plainly visible after maceration. This opinion 

 is now considerably strengthened by the interesting new 

 species, which I call M. hjorti in honour of the distin- 

 guished leader of the expedition. The five specimens 

 taken have suffered a good deal during capture. Only 

 one specimen is fairly well preserved, possessing both 

 tentacles intact, and it has been represented in pi. II. The 

 specimens were captured at the following stations: — 



Stat. 52. 1200 in. w. 3 specimens, dorsal mantle- 

 length 95, 85, 71 mm. 



„ 62. 3000 — dorsal mantle, length" 68 mm, 

 both tentacles well preserved. 



,, 63. ? dorsal mantle, length 55 mm 



badly damaged. 



Also a young specimen, dorsal mantle-length 30 mm, 

 taken at Stat. 52 1200 m. w. evidently belong to this 

 species. 



The measurements of the large specimen from Stat. 

 52 are as follows: 



Ventral length of mantle 92 mm 



Dorsal ,, - ,, 95 „ 



Total breadth of both fins 102 ,, 



Length of body to base of 4th arm 120 „ 



Length of right fourth arm 73 „ 



Length of left „ „ 75 ,, 



Length of dorsal arms 44 ,, 



Breadth of head 41 „ 



Length of funnel cartilage 6 „ 



Maximum breadth of mantle 35 „ 



Diameter of eye 26 ,, 



„ - lens 9 „ 



As we see from these measurements our species is 

 above all characterised by an enormous breadth of the 

 fins, which are located on the dorsal side of the pointed 

 mantle and reach nearly to the anterior edge of the mantle. 

 This character appears even in younger specimens and 

 offers a striking point of difference from the other species 

 of Mastigoteuthis, in which the fins never are so enormously 

 developed. The fin is generally of a rhombic shape, the 

 corners being somewhat rounded. 



The head is blown up by the huge eyes, presenting 

 cheek-like protruding folds towards the short neck. On 



Fig. 1. Mastigoteuthis Hjorti. Stat. 52. 



these folds are situated the two short-stalked olfactory 

 tubercles, 2 mm long and terminating in an acorn-shaped 

 point. The funnel is of moderate size and is surrounded 

 by the cheek-like folds of the head. The funnel cartilage 

 is relatively small, oval or egg-shaped, the exterior and 

 posterior edge protruding slightly without, however, forming 

 a distinct tragus and antitragus. 



The arms are on the whole moderately long and 

 exhibit the length-relation typical for Mastigoteuthis viz: 

 4, 3, 2, 1, They are feeble, angular, provided with 2 rows 

 of comparatively small stalked and ball-shaped suckers, 

 of which the largest measure 1-3 mm. in diameter. The 

 suckers are characterised by 9 or 10 tack-shaped little 

 teeth fringing the dorsal edge; the teeth are not pointed, 

 and continuously decrease in size towards the sides. 

 Protective keels or webs are poorly developed, and only 

 the ventral arms exhibit a marked development of swim- 

 ming webs or membranes. The skin of the buccal runs 

 into 7 flaps, of which the ventral ones are triangular, 

 somewhat close together, and fixed to the ventral side 

 of the ventral tentacles. 



