302 



BULLETIN OF THE BUREAU OF FISHERIES. 



Fig. 9. — Dosidicus gigas, foveola. [72.] 



Arms robust at the base but becoming very- attenuate toward the long and slender tips; order of 

 length 3,2, 1, 4, the first three pairs nearly equal, the ventral pair much the shortest ; all furnished with an 

 acute membranous keel along the outer margins attaining its greatest prominence on the much flattened 

 and compressed third arms. Along the ventral margin of the sucker bearing area of the third arms is a 

 broad tenuous swimming membrane supported by numerous stout, transverse, conical processes (tra- 

 beculae) having their origin just in front of the base of the sucker pedicels and apparently in close relation 

 with them; along the dorsal margins of these arms and along both margins of the remaining arms this 

 membrane becomes much reduced, but the trabecule persist and extend out past it as conical tentacle- 

 like processes of a very characteristic appearance ; distally 

 the membrane is better developed and extends to the tips 

 of the trabeculae, even exceeding them to as great a dis- 

 tance again on the ventral edge of the third arms (pi. X1.IX, 



fig- 3)- 



Suckers large, oblique, hood-shaped , ranking in two 

 regularly alternating rows; pedicels short, stout, their 

 bases much swollen (pi. XLix, fig. 5); homy rings with 

 about nineteen sharp conical teeth, very small at the 

 lower, edge the upper median and two extreme lateral 

 teeth notably the largest (text fig. 10). Above condition 

 prevalent on the arms for only about half their length; 

 at this point begins the region of attenuation , simultane- 

 ously the suckers being suddenly reduced to a size quite incom- 

 mensurate with not only their former proportions but the gigantic 

 dimensions of the entire animal as well ; a reduction to a diameter of 

 about I mm. is attained almost at once, and thence they become 

 smaller and smaller until at the tip of the arm their structure is 

 barely to be perceived by the unaided eye. At the same time they 

 become much more crowded and their pedicels and marginal mem- 

 branes also undergo reduction, but not to such an extent as the suckers 

 themselves (pi. xux, fig. 4, 6). On the second arms (e. g.) the reduc- 

 tion begins gradually at the tenth pair of cupules, becomes suddenly 

 accelerated at the sixteenth, and distal to this point, occupying but 

 about one-half the total length of the arm, over 150 pairs of suckers 

 are to be made out without a lens. 



No hectocotylization known to occur. 

 Tentacles stout, robust, and relatively not very long; laterally compressed, outwardly keeled; 

 inner edge flattened and equipped with a narrow marginal membrane on each side as well as short tra- 

 beculse very suggestive of some of those already noted on the sessile arms. Club large, somewhat 

 expanded, lanceolate; about three-sevenths as long as the entire tentacle; the outer keel reaching a 

 high state of development toward the extremity; about fifteen pairs of large, deep suckers along the 

 middle, with a row of much smaller basin-shaped suckers along the marginal web on either side; sup- 

 ports of marginal web bifurcate, the lateral suckers having their origin far out upon the web at the point 

 of bifurcation , at its inner end each trabecula connected by a further pair of bifurcating ridges with the 

 similar ridges from the trabecula; just anterior and posterior of the opposite side ; distally the suckers 

 of all four rows become more nearly equal, much reduced, and much crowded, those of the ventral row 

 being slightly the largest and those of the dorsal row the smallest. Dorsal margin of the carpal region 

 of the club conspicuously armed with a fixing apparatus, comprising four heavy, fleshy pads, alternat- 

 ing with three comparatively small suckers, the homy rings of which are smooth; the median rows of 

 suckers cease just below the most distal pad, but those of the ventral row persist to a point nearly opposite 

 the most proximal tubercle (pi. xux. fig. 2). Homy rings of the large median suckers with about twenty- 



Fig. 10. — Dosidicus gigas, horny ring 

 from large sucker near base of second 

 arm, X 4- [72. 1 



