MUSEUM OF COMPARATIVE ZOOLOGY. Zo") 



The same, surface is covered by a network of muscular fibres, similar to that 

 found on the inner walls of the oral lappets of Bolina, and other genera. 

 Lips (/) simple, very flexil^le, and prominent, projecting below the mouth. 

 The auricles (a) are stout and not very prominent. There are two swimming 

 combs on each ambulacrum. The course of the chymiferous tubes does not 

 differ from that of the vessels of Bolina. The lateral or subtentacular tube 

 (I t) arises from the lower end of the funnel (fn), and passes down along the 

 side of the body into one of the lips. At this point it bifurcates (b), sending 

 a branch (6') on eacb side to join the tube (st), which arises from a short 

 ambulacrum.* The vessel later formed by the union of these small tubes 

 first skirts the margin of the auricle (a) and is then continued in the tube (t) 

 around the rim of the oral lappets, joining half-way in its course a similar tube 

 from the opposite side of the body. The branch from the lateral tube joins 

 the auricular vessel just below the auricle. , 



The chymiferous vessels of the eight rows of swimming plates (amhulacra) 

 primarily branch from the lower end of the " funnel " as two small lubes 

 (fig. 6, c) on opposite sides of this medial vessel, in a vertical plane at right 

 angles to that which passes through the longitudinal axis of the mouth (fig. 5). 

 The plane in which they lie cuts at right angles the axis of the mouth and 

 passes through the otocyst (fig. 5, c). Each of these primary branches bifur- 

 cates, at a short distance from its origin (c), and each smaller branch again 

 subdivides (c c) into two members. In this way we have formed the eight 

 vessels, which extend to the surface of the outer body walls, and form the 

 meridional tubes, which lie directly under the rows of combs. The tubes (s t), 

 which correspond to the " longer rows " of combs in the Bolinidcc, push their 

 Avay into the oral lappets, and join in pairs, two in each lappet, while the 

 shorter rows, after a more tortuous course, in which they unite with the bi- 

 furcations from the lateral tube {I t) and skirt the edge of the auricles, also 

 eventually unite in the oral lobes, forming a loop, which encloses the union 

 of the vessels (s t).-\ In the union of the " long tubes " adjacent vessels 

 unite ; in the junction of short tubes, vessels separated by a pair of long tubes 

 join. 



The otocyst resembles that of Bolina. 



No liver glands or folds of the intestine and stomach were observed. 



In Dr. Chun's :j: figures of De'iopea the tubes corresponding with the vessels 

 (s t) end blindly in the oral lappets without junction. In Ocyroe these tubes 

 join as shown above. De'iopea has tentacular filaments extending from the 

 position where the tentacle hangs to that of the auricles, along the lower edge 

 of the body. Tentacular filaments are wanting in 0. crystallina. 



Dr. Chun, J as is Avell kno^vn, divides the Cteno})hora into the two groups 



* Tlie ambulacrum adjacent the tentacle on either side. 



t These tubes are shorter than the others in the adult. They correspond with the 

 "long tubes " in the yoimg Bolina. 

 t Op. cit., PI. IV. figs. 2, 3. 



