Prof. H. A. Nichohon — On Fossil Tubicolar Annelides. 55 



rently destitute of any cellular structure. Cast of the tube composed 

 of short conical rings, its surface completely smooth, and destitute of 

 striae or furrows. 



ConchicoUtes gregarius, Nich. — Tubes closely in contact, attached 

 by their smaller ends to dead shells. Tube varying in length from 

 a quarter to half an inch, and having a diameter at its mouth of about 

 half a line. Conical rings which compose the tube about four in 

 the space of a line. 



I have now to describe a very distinct and beautiful species of this 

 genus, which has been forwarded to me through the kindness of 

 Prof. Edward Orton, of the Geological Survey of Ohio, and for which 

 I propose the name of ConchicoUtes corrugatus, from the strongly- 

 marked annulations of the tube. 



ConcJiicolites corrugatus, Nich. — Tubes growing socially in clustered 

 masses upon the shells of molluscs ; calcareous ; destitute of vesicular 

 structure ; conical, and gently curved. Attached by their smaller 

 extremities, sometimes for the space of a line or more ; and either 

 partially free, or contiguous to one another throughout the remainder 

 of their course. Length of the fully-grown tube -^ inch or a little 

 more ; diameter of tube at mouth -j-'-q inch. Tube composed of 

 conical imbricating rings, about forty in the space of an inch (about 

 four in the space of ^ 6" inch) , giving the tube a strongly annulated 

 appearance. 



The exquisite preservation of the specimen from which the above 

 description is taken (Plate IV. Fig. 2) enables me to settle definitely 

 certain points connected with the structure of ConcJiicolites, about which 

 my specimens of C. gregarius had left me in doubt. It is now certain, 

 as I had previously conjectured, that the tubes in this genus agree 

 with those of the modern Serpulce in being calcareous, and that they 

 differ altogether from the extinct genus Cornulites in being alto- 

 gether destitute of any cellular structure. They differ from Serpulcs 

 in having the tubes composed of a succession of imbricated rings, 

 the wider ends of which are directed towards the mouth of the tube. 

 From the extinct Ortonia, again, they differ, not only in the circum- 

 stance just mentioned, but in their social clustered habit of growth, 

 and in the fact that the tube is not attached along the whole of one 

 of its sides. 



The specimen figured exhibits the tubes of more than thirty 

 individuals of ConcJiicolites corrugatus attached to the spire of 

 Cyclonema T)ilix, Conrad. The tubes are all attached to the shell 

 by their smaller ends, and radiate from their points of attachment, 

 somewhat like the spokes of a wheel. Each tube is conical, circular, 

 or nearly so, in section, and widening out gradually from its apex to 

 its mouth. When carefully examined, it can readily be made out 

 that the tiibe really consists of a succession of short calcareous rings 

 of a conical form, inserted one within the other — this structure being 

 especially perceptible in the interior of the broken tubes. From the 

 exterior, however, the appearance is more that of a succession of 

 strongly marked ridges or annulations, which completely surround 

 the tube, and are separated by slight depressions or flattened inter- 



