A. E. Verrill — North American Cephatopods. 29*7 



die; posteriorly much larger, with a long tubular cone. This re- 

 markable genus cliflFers widely from all others hitherto described in 

 the character of the tentacular arms and suckers. This, with the 

 great size of the caudal fin, gives a very peculiar aspect to the species. 



Mastigoteuthis Agassizii VerriU. 



Bulletin llus. Corap. ZooL, vol. vi, pi. 1, fig. 1 ; pi. 2, figs. 2, 3-3^, 1881. 



Plate XLVIII, Plate XLIX, figures 2, S-Sg-. 

 Body elongated, round anteriorly ; posteriorly tapering rapidly to 

 the slender, acute, terminal portion, which is confluent with the cau- 

 dal fin, to the tip. Front dorsal edge of mantle emarginate in the 

 middle. Caudal fin very large and broad, transversely rhomboidal, 

 obtuse posteriorly, its length, from origin to tip, about equal to half 

 the combined length of the head and body. Eyes large, with thin 

 lids, which appear to have had a distinct but very small sinus in 

 front; pupils circular ; iris brown, in alcohol. Sessile arras very une- 

 qual ; ventral arms much larger and longer than the others, about 

 equal to length of head and body ; dorsal arms very small, scarcely 

 one-third the length of the ventral pair; two lateral pairs nearly 

 equal, decidedly longer and stouter than the dorsal pair. A delicate 

 thin, marginal membrane extends along the arms, outside the rows 

 of suckers, to the slender tips. Suckers small, in two regular rows 

 on all the arms, subglobular, with small oblique apertures, surrounded 

 by small horny rings, which have a nearly entire margin, and by sev- 

 eral series of minute plates (Plate XLIX, fig. Zg). 



Basal web, between the arms, very small. In the smaller speci- 

 men, which is a male, the right ventral arm is longer than the left, 

 and the tip appears to have been flattened, and the marginal mem- 

 branes seem to have been wider, with the edges infolded, so as to 

 form a sort of furrow on the outer side, but the suckers are mostly 

 gone, and it is too much injured to be accurately described. Ten- 

 tacular arms long, more than twice the combined length of the head 

 and body, slender, round, gradually tapering to the tip, like a whip- 

 lash, the distal half of their length covered with very numerous, 

 crowded, minute, pedicelled suckers (fig. 3f?), which cover nearly the 

 entire surface along the terminal portion, leaving only a narrow naked 

 line along the back, but farther from the tip this naked space becomes 

 gradually wider and the band of suckers narrower, and after these 

 crowded bands of suckers cease, scattered suckers, placed mostly two 

 by two, extend for some distance along the proximal part of the arms. 

 The suckers of the tentacular arms are so small that their form can- 



