EXPLORATION OF ALASKA. 261 
TRIOPHA, Bergh, n. gen. 
Forma corporis fere ut in Triopis, sicut quoque margo fronta- 
lis; margo dorsalis appendicibus nonnullis nodosis vel breve 
ramosis. Tentacula compresso-poculiformes (auriformia) ; rhino- 
phoria retractilia, clavo perfoliato. Branchia quinquefoliata, 
foliis tripinnatis. 
Os lamellis duabus fortioribus e baculis minutis compositis 
armatum. Lingua rhachide dentibus spuriis (4); pleuris denti- 
bus lateralibus 3-4 (corpore processu aleformi et hamo ap- 
planato instructis) et serie dentium externorum (10-11) armatis. 
Prostata ? 
This interesting form, that forms a link between Polycera 
and Triopa on one side, and the Luplocami on the other, ap- 
proaches more nearly to the latter than to the former. 
In the exterior, the Zriophe! resemble the Triope, but still 
_ differ in some points sufficiently. The appendices of the back 
are more composite; the tentacles seem different from those of 
the Triope (which have them folded lengthwise and obtuse at 
the end; see for comparison, Pl. XV, fig. 12); they are com- 
pressed cup-shaped or auriculate. The gill contains five leaves. 
Whilst the Zriope want an armature of the true mouth,’ the 
Triophe are provided with two strong plates (composed of 
densely set staffs). Whilst the rhachis of the tongue in the 
Triope is naked, the Triophe show four false plates, (** bosses” of 
Dall, simple thickenings of the base membrane of the radula), 
here; instead of the two peculiarly formed lateral plates on the 
pleure in the Triopa,? the 7riophe have three or four lateral 
plates (with a wing-like process of the body and a depressed 
hook) ; with, on the outside of these, a series of (ten to eleven) 
uncinal plates, nearly as in the 7riope. After all, the Triophe 
are closely allied to the Colg@,4 and essentially differ from these 
1 Having at first and rather superficially examined the exterior, I first 
regarded the animal as a T'riopa, and called it so [s. part I, p. 128 (72), 
and the Plates (XIV, XV)]. 
2 See for comparison Pl. XIII, fig. 19. 
3 See for comparison Pl. XIV, fig. 21, 22. 
* The diagnosis of the Colgw would be: 
Forma corporis fere ut in Triopis. Vaginz rhinophoriales calyciformes 
oblique ; rhinophoria retractilia, clavo perfoliato. Tentacula auriformia. 
