4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ra 



arises from the anterior apex. The ventral members are large and 

 oval. No trace of a funnel valve exists (pi. 4c). 



The head is elongate; toward the anterior end it bears large pro- 

 truding eyes that are directed slightly forward. The "olfactory" 

 organs are situated posterior to the eyes on long, slender stalks. 

 Nuchal crest and nuchal folds are lacking. Two heavy, muscular 

 bridles extend from the cephalic cartilage along the ventral surface of 

 the head and attach to the dorsolateral sides of the tubular portion 

 of the funnel. The cephalic vein lies close to the surface in the midline 

 between the bridles (pis. lc, 2b). 



The arms are weak and slender and arranged in the order 4-3 = 2-1. 

 The dorsal three pairs of arms bear biserially arranged suckers through- 

 out their length. In some specimens, the ventral row of suckers of 

 these arms possesses two to four moderately enlarged suckers located 

 about two-thirds of the distance along the length of the arm. Prob- 

 ably this represents a sexual dimorphism, but because the specimens 

 are insufficiently developed, the sexes cannot be determined in all 

 cases. The sucker stalks are short and arise from large, conical bases. 

 The chitinous rings are large but possess very small apertures that 

 bear approximately 7-10 (average 8) short, broad, truncate teeth 

 that are separate along the distal half of the margin. In the proximal 

 half, the teeth are fused, giving a smooth margin that becomes slightly 

 scalloped laterally (pi. 4k-n). The dorsal three pairs of arms appear 

 to bear low keels, particularly along the distal portions. The arms, 

 however, have been injured so that the true nature of the keels is difficult to 

 determine. Protective membranes are developed weakly and, al- 

 though they are not supported by distinct trabeculae, their margins 

 are scalloped. 



The ventral arms are extremely long, slender, and fragile and have 

 large lateral membranes that extend their full length. The suckers 

 originate in two rows at the base of each ventral arm but gradually 

 tend to converge into a single row near the middle of the arm. These 

 suckers are extremely small and decrease in size toward the middle 

 portion of the arm, where they disappear, leaving the distal half of 

 the arm naked. No protective membranes or trabeculae occur on 

 arms iv. 



Tentacles are long and slender; they bear very short, simple clubs. 

 Keels are not apparent. The protective membranes form an indis- 

 tinct ridge and trabeculae are indistinguishable (pi. Id). The carpal 

 area bears approximately four to five small suckers that alternate 

 in two longitudinal rows. The outer chitinous rings of these suckers 

 are narrow bands. The inner rings have three superimposed rows of 

 small, rounded knobs; the outer row bears about 15 knobs. The 

 smaller knobs of the inner rows alternate with those of the outer row 



