14 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 



Grabe, 1901, finds that in Pleurohrachia pileus the anlagen of the 

 sexual cells are found, not only in the 8 meridional canals, but also in the 

 paragastric and tentacular vessels. The sex-cells are apparently of ecto- 

 dermal origin, as R. Hertwig, 1880, found them to be in other ctenophores. 



L. Agassiz, 1849, gives beautiful figures of P. pileus. 



Pleurohrachia brunnea sp. nov. (Figs. 2 to 4, plate 1.) 



This species may be at once distinguished from the more northerly 

 Pleurohrachia pileus by its more oblong, egg-shaped body, and especially 

 by the opaque yellow-brown color of the stomodaeum and the terminal 

 knobs of its tentacles. 



The body is egg-shaped with but little lateral compression and is 

 12 mm. long. The 8 ciliated tracts are of equal lengths and extend over 

 the middle two-thirds of the sides of the body. The 8 meridional canals 

 extend downward a considerable distance beyond the combs of cilia 

 and end blindly without anastomosing. The 2 tentacles arise from deep 

 clefts which open to the exterior at the middle of the aboral half of the 

 sides of the body. Each tentacle gives rise to about 32 simple side 

 branches, which often coil into helices and are highly contractile. The 

 main shaft of each tentacle terminates in a large, knob-shaped end. A 

 row of deep purple pigment spots extends half-way down each tentacle 

 shaft on the abaxial side, and the side branches of the proximal halves 

 of the tentacles are also dotted over with these purple spots. The ten- 

 tacles differ markedly from those of Pleurohrachia pileus in their fewer 

 side branches and in the fact that they end each in a large knob. 



This species was found by the author in large swarms off the coast 

 of New Jersey, from Sandy Hook to Barnegat Bay, on October 16, 1904. 

 It is separated from Hormiphora plumosa by the greater length of its 

 meridional vessels, which extend a considerable distance beyond the oral 

 ends of the rows of combs instead of ending with the combs, as in H. 

 plumosa. The bases of the tentacles are not closely applied to the sides 

 of the paragastric vessels as in Hormiphora, but are widely separated. 

 Moreover, in H. plumosa the lower (oral) ends of the tentacle-sheaths 

 are slightly below the ends of the meridional canals, whereas in P. brunnea 

 the meridional canals extend below the ends of the tentacle-sheaths. 



P. brunnea bears a closer resemblance to Hormiphora spatulata Chun, 

 from the Canary Islands and the Straits of Gibraltar, but its cihated 

 combs begin at a greater distance from the apex than in H. spatulata, 

 and the tentacles of P. brunnea terminate in knob-like ends instead of 

 tapering to points. H. spatulata is described by Chun, 1898, Ctenophoren 

 der Plankton Expedition, p. 18, Taf. 2,3. 



Genus HORMIPHORA L. Agassiz, i860. 



Cydippe, Gegenbaur, 1856, Archiv fiir Naturgesch., Jahrg. 22, p. 200. — Sars, M., 

 1856, Middelh. Litt. Fauna, p. 71. — Panceri, 1872, Atti Acad. Napoli, vol. 



5. P- 2. 

 Hormiphora, Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, p. 196. — Chun, 

 1880, Ctenophoren des Golfes von Neapel, p. 280; also, 1898, Ctenophoren 

 der Plankton-Expedition, p. 16. — Moser, 1903, Ctenophoren der Siboga- 

 Expedition, pp. 9, 31; 1908, Abhandl. Akad. Munchen, Supplement Band i, 

 Abhandl. 4, p. 10; 1909, Ctenophoren der deutsche Siidpolar-Expedition, 

 Bd. II, Zool. 3, p. 148. 



