1879.] NATURAL SCIENCES OF PHILADELPHIA. 93 



The salivary glands were very long, accompanying the oeso- 

 phagus (cf. PI. III. fig. 12a) and extending further backwards; 

 the duct was also rather long (fig. 126). 



The oesophagus, stomach, and intestine were as in the typical 

 species. The liver, perhaps in consequence of occasional contrac- 

 tion of the animal, much thinner anteriorly, much thicker poste- 

 riorly, and of a more grayish color. 



The heart was as usual. The renal syrinx nearly equalled the 

 ventricle of the heart in size. The renal organ, as far as could be 

 determined, was as in the Aeolidiidse. The hermaphroditic gland 

 almost as in the typical species 1 covering the back of the liver 

 from the anterior end of this organ (or nearly reaching the ante- 

 rior genital mass) to a point between the last pair of branches for 

 the dorsal papillae. The gland forms a rather thick layer, which 

 is a little narrower than the liver, and fills the longitudinal median 

 groove in the upper side of it. It is of a slate gray color, owing 

 to the peculiar pigment of the single glands ; is composed of a 

 mass of rather large, rounded, isolated, but (from reciprocal pres- 

 sure) often subangulated glands (cf. PI. II. fig. 15). 



Neither developed zoosperms nor large oogene cells were found 

 in the glands of the individual examined. The anterior genital 

 mass was whitish and yellowish : and, as far as could be deter- 

 mined, quite as in the Dendr. arborescens ; a very large part of 

 the whole mass was formed by the long penis, which still seemed 

 somewhat shorter than it usually is 2 in the typical species (cf. PI. 

 IV. fig. 4). 



This form might, perhaps, prove to be identical with the form 

 of Dendronotus " with the tips of the branchial tufts white," 

 fished by Couthouy (U. S. Explor. Exped. Moll., 1852, p. 311), in 

 Puget Sound ; or even to agree with the D. iris of Cooper (1. a). 

 Under the circumstances, the form described above must very 

 likely be regarded as a new species, not even identical with the 

 nearl}' red Tritonia pulchella of A. and H. (Ann. Mag. Nat. Hist, 

 iv. 1842, p. 33), which, like all the forms of D. arboi*escens is still 

 dotted with yellow (cf. A. and H., Monogr., Part I., 1845, fam. 3, 



1 The representation by Alder and Hancock (1. c, PI. II. fig. 1?) is incor- 

 rect. 



2 The penis seems to vary a good deal in the Dendron. arborescens, or a 

 least to be very contractile. 



