A. E. Yerrill — Worth American Cephalopods. 285 



{ho) of the gills ; the anterior passing into the anterior aorta {ad) ; 

 the posterior, median one, eontinnons with the posterior aoi'ta, gives 

 off, first a small ventral branch, which supplies the reproductive 

 organs, and then later a median venti*al artery (o), going to the 

 mantle ; while much farther back it divides into two branches (o', o') 

 which supply the sides of the mantle and caudal fin. The branchial 

 auricles {cm) are large and ovate, with a small round capsule at the 

 posterior end. 



The urinary organs or ' kidneys ' (r, r) are voluminous, lobulated 

 organs, intimately connected with the venae cavae, and mostly situated 

 below and in front of the heart, but there is a more compact glandular 

 portion (r') extending, as usual, backward along each of the posterior 

 venae cavae {vc") in the form of a long pyriform gland. Just in 

 front of the bases of the gills, on each side, there is a circular opening 

 {u) through the peritoneal membrane, which probably gives exit to 

 the urinary excretions. 



The reproductive organs of the female, however, present the 

 greatest divergence from LoUgo, and allied forms. Instead of hav- 

 ing a single large oviduct, on the left side only, and opening far for- 

 wai'd, we find, in this genus, two small oviducts {ocl) symmetrically 

 placed and opening much farther back. Moreover, instead of the 

 large and very conspicuous, unsymmetrical nidamental glands, situated 

 in front of the heart, as in Loligo, we find in Ommastrephes much 

 smaller and simpler glands (a'cc) situated much farther back, side by 

 side, near the median line. 



The ovary (ou) is a long, pyriform, lobulated organ ; its anterior 

 end is attached to the posterior end of the stomach, and is divided 

 into several short lobes, which clasp the end of the stomach ; its 

 small posterior end extends backward into the concavity of the 

 hooded portion of the pen {p"). 



The spermary or testicle of the male (Plate XXXVIII, fig. 2, i) 

 occupies the same position as the ovary ; it is a more compact organ, 

 with a smoother surface, and the anterior lobes are longer and 

 narrower and extend farther forward along the sides of the stomach. 

 The prostate gland and other male organs resemble those of Loligo 

 (see Plate XL, figures 1, 2). 



It must be borne in mind, however, that none of the specimens 

 examined were in their breeding season. Consequently the repro- 

 ductive organs were all much smaller and less conspicuous than they 

 would have been in breeding individuals. This is particularly the 

 case with the ovaries and spermaries, but the same remark would 



