38 bulletin: museum of comparative zoology. 



single instance diil I find any of them bearing a sucker. On the first arm 

 there are only three or four of these, very low down close to the buccal mem- 

 brane ; on the second they are slightly more numerous, on the third there are 

 seven or eight, which form a triangular patch with the apex directed towards 

 the root of the arm; on the fourth right arm there are about a dozen sim- 

 ilarly disposed. 



The fourth left arm (Plate 8, Fig. 5) further shows a remarkable form of 

 hectocotylization. This is produced chiefly by a development of the lappets 

 and web along the ventral margin of the sucker-bearing surface. The web 

 becomes rapidly broader from the proximal end, until at a point about one- 

 third along the arm its breadth is three times the diameter of the arm : hence it 

 becomes gradually narrower, running off into the arm just before the tip. The 

 lappets are correspondingly lengthened and form a series of parallel ribs 

 strengthening the membrane. Along their margins (Plate 8, Fig. 6) may be 

 seen a series of minute papillae like those described on the other arms. On 

 the dorsal margin of the sucker-bearing face is a row of lappets, also provided 

 with rows of papillae, but I was not able to find any trace of a web uniting 

 them. However, as the web is in all cases very delicate, it is quite possible 

 that it may exist. At the root of the arm is the triangular group of papillae 

 alluded to above. 



Tlie Radula, which has not been hitherto described, is figured on Plate 8, 

 Fig. 9. It consists of the usual seven longitudinal series : the centrals are ex- 

 tremely simple, an acute point arising from a plain rounded base ; the points 

 diverge from the middle line, sometimes to the right, sometimes to the left, 

 only about one in six being quite symmetrical. The first laterals have a 

 strong pointed tip mounted towards the median aspect of a simple base, the 

 points being directed somewhat inwards ; the second laterals are stout, curved, 

 and pointed ; the third laterals are much larger, comparatively more slender 

 and blunter than the second, and are bent to about the quadrant of a circle. 



38. Abraliopsis, sp. ? 



(Plate 2, Fig. 3.) 



Hahitat.—Stai'um 2G19 IIy«l., Gulf of Panama; March 11, 1891 ; lat. 7° 31' 

 N., long. 78° 42' 30" W., surface to 300 fathoms; temperature, surface G8° ; one 

 specimen; immature. [11.64.] 



SUition, 14, north of the Manjuesas Islands; September 7, 1899; lat. 6° 41' 

 N., long. 137° VV. ; 150 fathoms to surface; teuiperatnre, surface, 82°; one 

 specimen. [H. 143] 



My frien<l Dr. Pfeffer, who examined the former of the above-mentioned 

 young specimenH, considera it to belong to the /16ra/i()/)mgroup, partly because 

 of the length of the tentacles, and partly because at the extremity of the left 

 ventral arm (the right bt-ing imperfect) is to be seen a slight knob-like swtll- 

 ing, which might be a stage in the development of the curious pigmented 



