Banarls on the Gem(S ConchicoUtes of Niehoh^on. 11 



twisted into a flat spiral. I can detect no lonjiitudinal striatiun, but 

 the tube is covered with very numerous transverse ridges (at least 150 

 in the space of an inch), which are generallv better marked on the 

 sides than on the back of the tube. In very small, presumably young 

 specimens I have been unable to determine the existence of these 

 ridges, and even in fully grown examples they are more strongly 

 marked in some than in others. The tube is always attached along its 

 Avhole length, and in no case is any portion free, as is the case in Con- 

 cJiicolites." 



Prof. Nicholson had other specimens from Cincinnati, of which he 

 said : 



"They consist of minute, conical, flexuous or curved tubes, about 

 jLth inch in length, opening by a circular aperture at their widest ex- 

 tremity, and having their surface wrinkled with irregular rings or 

 anr.ulations. In all their essential characters these tubes seem to agree 

 with Ortonia minor; but they differ in the very important point that 

 they are not attached to any foreign body, but, on the contrary, are 

 perfectly free. I do not think they can possibly be referred to Ten- 

 taculites, since they are flexuous, or in some cases irregularly curved, 

 Avhile thev are destitute of the strong and regular annulations of the 

 typical species of this genus. Xor can they be referred to Ortonia, un- 

 less we believe their occurrence in a free state is an accidental circum- 

 stance, due to their having become detached from the body on which 

 they grew, prior to fossilization. This is a possible explanation, though 

 an unlikely one. At present I am inclined to believe that we have here 

 a Tubicolar Annelide, which, like Ditriqm, was free in habit; but I shall 

 delay naming and describing these remarkable fossils until I may be 

 provided with more ample materials." 



Ortonia conica (Nicholson), October, 1872. [London Geological 



Magazine, vol. ix., p. 448.] 



The Oiionia conica is described as follows by Prof. Nicholson : 

 " Tubes growing attached to the shell of some mollusc, varying in 

 length from J to |^ inch, with a diameter of about -jLthofan inch at the 

 mouth. Lateral annulations of the tube varying in number from 30 

 to 35 in the space of an inch. Surface smooth and completely desti- 

 tute, so far as observed, of longitudinal strice. Tubes truly solitary. 

 Location and position, Cincinnati, Ohio." 



The specimen here engraved (fig. 4) is from the same cart load of 

 earth that produced the specimen figured by Prof. Nicholson in the 



