PEKNATULIDA DREDGED BY H.M.S. "TRITON." 121 



Concerning the mode of capture, it will be seen from the above table that 

 the trawl was distinctly more successful than the dredge ; and the difference 

 between the two is greater than appears from a mere comparison of the number 

 of specimens taken, for the proportion of imperfect and mutilated specimens 

 brought up by the dredge far exceeds that yielded by the trawl, the mutilation 

 being in many cases clearly caused by the dredge itself. 



For such forms as Pennatulida the dredge is indeed a very unsuitable 

 instrument of capture ; a point that deserves a greater amount of practical 

 attention than it appears yet to have received.* It is certainly worthy of note 

 that the three most interesting forms collected by the " Triton " were all 

 brought up by the trawl. 



Concerning the nomenclature adopted, I have retained the terms polyp and 

 zooid for the two kinds of individuals, sexual and asexual, of which a Pennatulid 

 colony normally consists, since these names are in general use. Strictly 

 speaking, the names are objectionable, for the term zooid is commonly and con- 

 veniently employed in zoology to indicate any member of a colony that is 

 produced asexually, and in this sense both kinds of individuals of the Penna- 

 tulid colony are zooids. 



For the tubular cavity into which the mouth leads, and which is commonly 

 spoken of as the stomach, I have adopted the term stomodosum. This cavity is 

 in no sense of the word entitled to the name of stomach, inasmuch as diges 

 tion is effected, not in it, but in the body cavity into which it opens below. 

 Kolliker has proposed to call it oesophagus,! but the term stomodceum seems 

 preferable, as indicating at once its origin by involution of the outer layer of the 

 body or ectoderm. 



Description of the Specimens. 



Order PENNATULIDA. 



Section I. Pennatule^e. 



Sub-section 1. Penniformes. 



Family 2. Pennatulidae. 



Pennatula, L. 

 Pennatula phosphorea, L. (PI. XXI. figs. 4-7, and PI. XXII. figs. 8-16.) 

 This species was obtained by the " Triton " at two localities, off the Butt of 

 Lewis in 40 fathoms water, and at Station 11 at a depth of 555 fathoms. The 

 collection also includes a single specimen obtained by the "Knight Errant" in 

 1880. 



* Cf. Nature. A new dredging implement, voL xxvii. p. 11. 



f Kolliker, Anatorniscli-systematische Beschrelbung der Alcyonarien, p. 416, 1872. 



