10 THE VOYAGE OF H.M.S. CHALLENGER. 



and forty-eight at its edge ; the insertions of the mesenteries are recognisable by 

 longitudinal furrows ; the oral disc essentially larger than the pedal. 



In addition to the examples referred to above, there belongs to this species one 

 specimen from Station 299, December 14, 1875 ; Lit. 33° 31' S., long. 74° 43' W.; depth, 

 '2160 fathoms. — Dimensions, height, 1'3 cm.; breadth of the oral disc, 4 cm., of the 

 pedal disc, 1'7 cm. 



2. CoralUmorphus obtectus. — Twenty-four tentacles are situated on the oral disc, 

 and forty-eight at its edge ; the mesenterial insertions are covered, in the lower third of 

 the body-wall and the peripheral third of the pedal disc, by cylindrical thickenings ; 

 the pedal and oral discs of approximately the same size. 



To this species belongs only the example from Station 157, with which my former 

 description was concerned. 



Genus Cojynactis, Allman. 

 Corynactis (?) sp. (?)* 



The tentacles, both on the disc and at its edge, are knobbed ; those on the disc are 

 arranged in several circles, so that more than one tentacle communicates with each 

 intra-mesenterial chamber. 



Hahitat. —'^isitiou 219, March 10, 1875; depth, 150 fathoms. 



Dimensions. — Diameter of the oral disc, 2 '5 cm. ; height of the column, 0"8 cm. ; 

 greatest length of the tentacles, 1"6 cm. 



Angelo Andres gives in his monograph a description of the genus Corynactis, 

 based partly on personal observation, partly on the account of Allman, from which I 

 infer that, with one and the same radial chamber communicate one of the marginal 

 tentacles and, in many radii, several of those placed on the disc ; five cycles are present, 

 of which the first contains four tentacles, the second sixteen, the third, fourth, and 

 fifth twenty-four. Gosse records other numbers, namely, four rows with sixteen, twenty- 

 four, thirty-two, and thirty-two tentacles respectively. In such remarkable contra- 

 diction, one may well doubt whether one has any right to deduce a law of position from 

 either account; and the descriptions of the manner of distribution of the . tentacles 

 are so inadequate, that it is impossible to conjecture how many of the tentacles placed 

 on the disc correspond to a radial chamber. 



Amongst the Challenger material was an Actinian which I originally took for a 

 CoralUmorphus, till I recognised that on four radii of the body two tentacles on the disc 

 and one at its edge proceed from one and the same radial chamber. This is in contra- 

 diction to the law of the position of tentacles in CoralUmorphus, but on the other hand 

 is related to that in Corynactis ; to the latter genus I therefore provisionally refer it, even 

 though many characters do not agree in the two forms. Especially is its shape divergent, 

 being saucer-like as in CoralUmorphus, and not elongated as in Corynactis. Further, 



