10 Remarks on the Genus Conchicolites of Nicholso7i. 



riugs are just as visible on the interior of the tube as they are exter- 

 nally." 



"No reasonable doubt can be maintained as to the zoological posi- 

 tion of Ortonia. It is unquestionable that we have to deal here with 

 a true Tulncolar Annelide, nearly allied to the recent Serpuke. Ortonia 

 is still more nearly related to the extinct genus Cornnlites, from which 

 it differs in its much smaller size, and in being attached along the 

 whole of one side, instead of by its smaller extremity only. It differs, 

 also, in having the peculiar cellular structure of the tube confined to 

 a definite })ortion of its surface, and in being altogether destitute of 

 longitudinal striation. From ConchicoUtes, again, Ortonia is distin- 

 guished by the much more complete mode of its attachment, and by 

 the fact that the tubes are never attached socially, in clustered masses, 

 growing side by side, as is the case in the former genus." 



The specific character of Ortonia minor [Nicholson, February, 1873. 

 Lon. Geo. Mag., vol. x., p. 26], is as follows: 



" Tube calcareous, solitary, attached by the whole of one side to 

 some foreign object. Length of tube from ygth to VVths of an inch ; 

 diameter at mouth from 2^^-^^^ ^^ 2^5*'^^ ^^ ^^ inch. Tube marked with 

 transverse ridges or annulations, which are sometimes faintly marked 

 on the side opposite to the attached surface, and the number of which 

 is^ about fifteen in the tenth of an inch. Tube, in general, strongly 

 curved toward its smaller extremity." 



He says : "It does not appear to have any cellular structure of the 

 tube. In Ortonia conica, however, this cellular structure is confined 

 entirely to a small portion of the tube (namely, to that portion opposite 

 to the attached surface), and the absence of even this in the present 

 shows that it can not be regarded as a generic character. The only 

 approach to the same structure which I can detect in Ortonia minor is, 

 that the transverse rings, or annulations, which surround the tube, be- 

 come faint or obsolete on the side opposite to the attached surface. 

 Even this, however, is by no means constant, and the rings are some- 

 times completely continuous over the whole unattached surface of the 

 tube." 



" Though often occurring in great numbers' together, the tubes of 

 OHonia minor, like those of Ortonia conica, are, strictly speaking, 

 solitary ; that is to say, they do not, like the tubes of Serpuke, or Con- 

 chicoUtes, interfere with one another, or come into contact, except acci- 

 dentally. The tube is generally pretty nearly circular in section, 

 though sometimes slightly trigonal, conical, and always more or less 

 curved. Sometimes it is simply curved like a horn ; sometimes it is 

 curved like the letter S; and sometimes the smaller extremity is 



