232 



PALjEONTOLOGY of NEW-YORK. 



604. 2. MYELODACTYLUS BRACHIATUS (n. sp.). 



Pl. XLV. Fig. 7a-e. 



Fragment of an arm, somewhat semicylindrical or unequally pentagonal ; lateral appendages 

 cylindrical, strongly articulated ; canal transversely oval, with marks of muscular impressions 

 towards the circular margin very strongly impressed. 



Fig. 1 a. k. small fragment enlarged, showing two lateral appendages. 



Fig. 7 h. Transverse section of the same. 



Fig. 7 c. Section of one of the cylindrical appendages. 



Fig. 1 d. k. larger convolute fragment, with several appendages near the lower part. 



Fig. 7 e. The convex or outer side of this specimen, which has a depression along the centre, 

 from the upper part, nearly to the hase, where it gradually becomes obsolete. The 

 depression is marked bj^ two finer grooves along the centre. There are three appen- 

 dages on each side near the lower extremity, composed of elongated cylindrical joints 

 gradually tapering upwards. 



605. 3. MYELODACTYLUS % 



Pl. XLV. Fig. 8 a, &; and 9 c, b, c. 

 The fragments figured are similar to the preceding in many respects, but the section is 

 trapezoidal, the canal more extended transversely, and there are no appearances of lateral 

 appendages or tentacula. 



Fig. 8 a, 5. A fragment, which is compressed either naturally or by accident. The section 8 h 



shows the form of section. 

 Fig. 9 a, h, c. Another fragment, and the section, showing the difference of form in the two. 



The canal and character of muscular marking are precisely the same in each. 



Position and locality. All these fragments of columns and roots have been found in the 

 decomposing shale at Lockport. Many other fragments, showing distinct features, have been 

 found with these ; but the examinations I have been able to give them, have not been sufficient 

 to settle definitely their analogies with known species. 



