THE PENNATULIDA DREDGED BY H.M.S. " PORCUPINE." 461 



the rachis. The autozooids, twenty-one in number, as in the last specimen, 

 appear unusually long and slender: while the cell is but 3 mm. in diameter, its 

 length is 2 cm. to 2 5 cm., and that of the tentacles 1 to 5 cm. How much of this 

 apparent slenderness is due to the comparative amount of retraction of the 

 autozooids is, of course, doubtful, since, in spite of the great abundance of 

 spicules, the autozooids are highly retractile. 



iii. Station 47, 1869. — Five specimens, in length 4 to 6 cm., distinctly belong- 

 ing to the var. durum of Kolliker, were obtained here. 

 l Koll. (3), p. 304, pi. xxi. figs. 179-181. 



Family 3. Protocaulidse. 

 Genus Deutocaulon (Nob.). 



Deutocaulon hystricis (sp. n.), PI. XXXII. figs. 8, 9. 



This new genus was dredged at Stations 1 and 24 in 1869. It is of inter- 

 mediate complexity between Protocaulon, which may be regarded as the simplest 

 and most primitive Pennatulid, and such forms as Cladiscus and Svava. To 

 the former it approaches nearly, in the fact that the autozooids arise singly; to 

 the latter, in the formation of incomplete leaves by partial union of two or three 

 autozooids. 



To discriminate exactly between generic and specific characters, when but 

 one species has been obtained, is naturally not practicable ; but the following 

 may be regarded as definitions approximately correct : — 



Deutocaulon, genus novum. " Pennatulida ex familia Protocaulidarum, 

 quorum autozooidea, singulatim orta, pennse laterales fiunt : calyx nullus : axis 

 cylindratus." 



Deutocaulon hystricis, species nova. " Rachis erecta, gracillima, cuius utra- 

 que facies levis est, et sine sulco medio ullo: stipitis pars inferior tumida, infima 

 unca. In infima rachidis parte autozooidea lateralia, singulatim alterna- 

 timque posita ; in media rachide, pennae, primum alternse, turn adversse, ex 

 duobus — tribus polypis fiunt. Spicula nulla. Siphonozooidea (?)." 



All of the specimens, four in number, are very badly preserved, so that it is 

 difficult to determine their characters. 



The sarcosome is very thin throughout. No distinct cell nor any calycal 

 processes were observable in the retracted autozooids; but at the tops of the 

 radial chambers were collections of non-calcareous particles, very bright by 

 reflected light. Reproductive organs were nowhere recognised in the speci- 

 mens. 



This form supplies a link, as was stated above, between the simpler 



VOL. XXXIII. PART II. 3 Y 



