52 



PENNATULIDA. 



To the south of Iceland also (St. 164) the steamer < Thor has taken an incomplete specimen. As a rule 

 there is only one row of polyps on each side of the rhachis. The polyps are arranged, partly 

 alternating, parti y in pairs almost opposite to each other; the zooids are upon the whole also ar- 

 ranged in a ventral and a dorsal row on either side; the rhachis is narrow and thin, ca. 1 — 2 mm broad, 

 provided on the dorsal side only, throughout its whole length, with a narrrow streak bare of 

 individuals (fig. 3, n); as is generally the case this streak becomes broader down towards the peduncle - , 

 on the ventral side also, there is a corresponding naked streak on the lower part of the rhachis, but 

 it soon disappears, and the opposite polyps of the two sides join, so that the separation is only marked 

 by the ventral zooids (fig. 2). The polyp-calyx is formed like a horn or (straight) cornucopia 

 abundantly provided with long, red spicules; the edge of the calyx has very slightly marked teeth 

 on the abaxial side, none of them distinct as a rule, and in no definite number anywhere; the axial side, 

 as is commonly the case in the genus Protoptilum, passes into the ccenenchyma; the length of the calyx 

 is 2 — 3 mm , the breadth 1 — i.i mm . The polyps are only provided with spicules along the aboral side of 

 the tentacle-stem. The zooids have a calyx of similar form and appearance as that of the polyps, only 

 much smaller. They are more numerous than the polyps; on the dorsal surface, there is generally 2 — 3 

 zooids opposite to each polyp on each side of the median streak, and one zooid between every two 

 polyps on the same side; on the ventral side there are considerably fewer, about half the number. 



The colour of the peduncle was yellowish white (in spirit, colourless), the calyxes of the polyps 

 and the zooids were a splendid bright red on account of the coloured spicules (till now the colour 

 has remained unaltered in spirit); the whole rhachis gets the same splendid colour due to the 

 individuals being placed close together. The polyps themselves, like the zooids, were yellowish-white, 

 apart from the red streak on the tentacle-stem, due to the spicules; towards the point of the tentacle, 

 however, the red colour becomes faint or disappears, partly because the spicules decrease in size, 

 partly because they lose the colour themselves. The naked streak on the rhachis is yellowish white. 



The calcareous axis is round, ca. o.4 mm in diameter. 



In three of the specimens where the whole peduncle is preserved, it ends in a bulb; in a 

 fourth (Nr. 1 of the table below) there is no indication whatever of any enlargement, a proof that a term- 

 inal bulb is here, just as little as in other sea-pens, of no importance whatever as a specific character. 



The spicules (triangular) are on the polyp-calyxes 0.240 — o.48o mm long, 0.016 — o.032 mm broad; on 

 the tentacle o.o64 mm long and up to o.oii2 mm broad. 



Of the specimens in hand the six, as mentioned before, have all been taken at one locality: 

 St. 40, south of Iceland, 62° N. Lat. 21 36' W. Long, 845 fathoms, bottom temp. + 3°.3 C; the bottom 

 dark gray mud with numerous shells of Foraminifera and Pteropods [Limacina). The seventh specimen 

 has been taken (by the Thor) at 62 10.8' N. Lat. 19° 36' W. Long., r 3/ 7 1903, depth 2150 metres. The 

 measurements are as follows: 



Nr. 



Total length in mm. 



Length of peduncle » 



Breadth of terminal bulb . » 



Greatest breadth of rhachis 



190 



S7 

 4 



2 



