[231] CEPHALOPODS OF NORTHEASTERN COAST OF AMERICA. 441 



Figure 6. — The same specimen. Connective cartilage from the base of the siphon; 

 natural size. 



Figure 7. — The same specimen. Transverse sections of some of the arms ; a, of dorsal ; 

 b, of second pair; c, of third pair; natural size. The suckers are omitted. 



Figure 8. — The same specimen. Rings of suckers of the sessile arms, enlarged 2 diam- 

 eters ; a, a', side and front views of the loth and 13th suckers of a ventral arm ; b, b', 

 side and front view of one of the largest suckers of a lateral arm ; c, c', side and 

 front views of one of the larger suckers of a dorsal arm. 



Figure 9. — The same specimen. Part of the border of one of the larger suckers (12th) 

 of the second pair of arms ; more enlarged, showing part of the dentate edge of the 

 horny ring, with a portion of the circle of small plates, attached to the membranous 

 border. 



Figures 4 and 7 are by the author; fig. 4 is a camera-lucida drawing. 



Plate XVIII. 



Figure 1, la. — Ommastrephes illecebrosus V. Young male from Provincetown, Mass. 

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

 front view ; 1^ natural size. 



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

 enlarged 1$ 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 § diameters. 



Figures 6 and 6a. — The same. Side and front views of a smaller distal sucker of the 

 lateral arms ; enlarged § diameter. 



Figure 7. — The same. 9 • Side view of the horny ring of one of the largest suckers 

 of the club ; enlarged 3| diameters. 



Figure 8. — The same. From Eastport, Me. Part of the teeth of the odontophorc, in 

 their natural positions; enlarged 10 diameters; a, median teeth; b and b', inner lat- 

 eral teeth ; c, middle lateral teeth ; d, outer lateral teeth. 



Plate XLX. 



Figure 1. — Ommastreplies illecebrosus. Male, \ natural size. Opened on the ventral side. 

 The peritoneal membrane, most of the renal organs on the right side, and the repro- 

 ductive organs, except the testicle (t), have been removed. M, mantle cut open; 

 F, caudal fin; P, posterior part of pen; S, stomach; S', coecal lobe; H, systemic 

 heart; c, the eye; b, olfactory or nuchal crests; d, siphon; /, /, connective cartilages 

 on the base of the siphon ; f, f, connective cartilages of the mantle, which fit into 

 /, /; m', lateral muscles of neck ; g, g, gills ; I, liver ; i, ink-sac ; h, intestine or rec- 

 tum; ao, anterior aorta, going to head ; bo, efferent branchial vessel ; o, median ven- 

 tral artery of mantle ; o', o', lateral arteries going to mantle and fins ; a u, branchial 

 auricles; v c, anterior vena-cava ; vc", posterior vena-cava of left side (the right one 

 has been removed) ; r r, saccular ventral renal organs ; r', more compact glandular 

 (renal) organ, connected with the posterior venae-cavse; t, testicle or spermary ; p", 

 hooded posterior tip of pen, inclosing the end of the spermary. From an alcoholic 

 specimen. 



Figure 2. — The same. Jaws ; enlarged 1£ diameters ; a, superior ; b, inferior mandible. 



Figure 3. — The same. Part of the teeth of the odontophore in their natural positions, 

 enlarged 25 diameters; a, median teeth; b and b', inner lateral teeth ; c, middle lat- 

 eral teeth ; d, outer lateral teeth. 



