A. E. Verrill — North American Cephalopods. 437 



Plate XXVIII. 



Figure 1. — Ommastrephes illecebrosus V. Young male from Province town, Mass. 

 General figure of ventral side, f natural size ; la, club of the right tentacular 

 arm, front view, enlarged If. 



Figure 2. — The same. Club and part of tentacular arm, of a larger $ specimen, 

 enlarged If diameters. 



Figure 3, 3a. — The same. Hectocotylized right ventral arm of a large male specimen, 

 from Eastport, Me., showing the sexual modification of the suckers and their 

 peduncles toward the end of the arm ; 3a transverse section of the modified por- 

 tion of the same. 



Figure 4. — The same. Pen of a young specimen ; f natural size. 



Figures 5 and 5a.— The same. Side and front views of a large sucker of the lateral 

 arms, enlarged 3f diameters. 



Figure 6 and 6a. — Side and front views of a smaller, distal sucker of the lateral arms. 



Figure 7. — The same. $ Side view of the horny ring of one of the largest suckers 

 of the club, enlarged 3f diameters. 



Plate XXIX. 



Figure 1. — Loligo Pealei Lesueur. Female from Vineyard Sound. Ventral view, |- 

 natural size; 1, dorsal arms; 2.3. 2d and 3d, lateral arms ; 4, ventral arms ; t, 

 tentacular arms ; a, nuchal olfactory crests, about the ear ; e. eye ; ^j, aquiferous 

 pore ; s, siphon. 



Figure 2. — The same. Tentacular arm of a large male, enlarged \\ diameters. 



Figure 3, 3a. — Front and side views of the hectocotylized left ventral arm of a male, 

 showing the sexual modifications of the suckers and their peduncles, toward the 

 tip, enlarged lA- diameters. 



Figure 4. — The same. Female. Front view of the beak and buccal membranes, 

 natural size : ??2, mandibles ; /, inner fold ; / second fold of the buccal membrane ; 

 a, dorsal ; &, c, lateral : d, A^entral angles of the outer buccal membrane, with 

 their small suckers ; s, peculiar horse-shoe shaped tubercle, or sucker, for the 

 attachment of the spermatophores, during copulation. 



Figure 5. — Ommastrephes illecebrosus. Side view of the head and siphon, after 

 removal of part of the mantle, f natural size ; 1, 2, 3, 4, bases of 1st to 4th pairs 

 of sessile arms; t a, base of tentacular arm; m, mantle; h,h', olfactory crests 

 around the ear ; d, siphon ; /, /', the connective cartilages for attaching it to the 

 mantle. 



Figure 5a. — The same. Lateral connective cartilage, or 'button' on the inside of the 

 mantle, which fits closely into the cartilage pit (/) on the base of the siphon. 



Plate XXX. 



Figure 1. — Rossia Hyatti Verrill. Female. Ventral view of the head and arms, en- 

 larged 3 diameters. 



Figure 1.— Rossia suhlevis Verrill. Female. Ventral view of the head and arms, 

 enlarged 3 diameters. 



Plate XXXI. 



Figure 1. — Rossia Hyatti. Dorsal view, enlarged 1-J- diameters. 

 Figure 2. — The same. A young specimen, enlarged 1-| diameters. 



