390 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
in front of the dorsal tentacles. Oral and dorsal tentacles nearly equal 
in length, moderately long, tapered, blunt. The dorsal tentacles appear 
slightly wrinkled transversely. Eyes black, conspicuous, near together, 
just behind the bases of the dorsal tentacles. Foot narrow, with broad, 
rounded anterior angles. Head moderately large, its outline nearly 
semicircular in front, and projecting considerably in advance of the 
bases of the oral tentacles. 
Color variable. In some specimens the nuclei of the dorsal papille 
and the biliary ducts from them are dark green, the nuclei appearing to 
be lobulated or floculent; the outer sheath is translucent whitish, with an 
interrupted streak of flake-white on the distal half, and with unequal 
specks and spots of the same scattered over the surface, while on the 
outer side, near the end, there is a patch of orange; tip translucent 
white. In front of the bases of the dorsal tentacles there is a dark 
green patch. Tentacles white. 
In other specimens, taken at the same time, the nuclei of the dorsal 
papille were salmon-colored, but the subterminal patch of orange and 
the streak and specks of flake-white were as in the green variety; the 
body was translucent white; dorsal tentacles white, tinged or faintly 
reticulated with flake-white ; oral tentacles with a streak of flake-white 
on the posterior side. 
Odontophore narrow, with a single row of teeth; these have thirteen 
sharp denticles, the median one scarcely as long as those next to it; the 
anterior border of the tooth is nearly semicircular, with a notch on each 
side near the outer ends, which run backward, as short processes, some- 
what enlarged and emarginate at the end. 
Off Cape Cod (station 328), in 23 fathoms, among hydroids, September 
6, 1879. 
This species is nearest allied to Cratena olivacea (Alder & Hancock), 
but differs in the form of its teeth, as well asin its coloration. It is also 
allied to Cratena viridis, of Europe. In case either of the older names 
(Cavolina and Montagua) be retained for this group, this species should 
be so named. But both of these names having been previously used 
for other genera, they should be discarded. 
Cratena gymnota (Couthouy) Verrill & Emerton. 
Montagua Gouldii Verrill, Invert. Viney. Sound, p. 667 (author’s copies, p. 373), 
1873. 
This species, which is common on littoral hydroids, from Massachu- 
setts Bay to New Haven, Conn., is a typical Cratena Bergh* (= Cavo- 
lina Alder & Hancock = Montagua auth.), and is very closely allied to 
C. aurantiaca (A. & H.) of Europe, with which its dentition agrees very 
nearly, even in minute details. In C. gymnota the coloration, also, is 
often similar to that of C. awrantiaca, but the dorsal papillze are fewer 
*TIn the excellent work of G. O. Sars this generic name has been, by some oversight, 
misapplied, in place of Cuthona, to include C. nana, which was the original type of 
Cuthona Alder & Hancock. 
