MONOGRAPH OF THE EXISTING CRINOIDS. 233' 



nulars, extend outward and slightly distally, and are somewhat more than twice as 

 long as broad and strongly constricted centrally, so that they appear as two similar 

 circles joined by a broad neck. Their reticulation is very fine, and the borders are 

 regular, though unfinished. 



The integument over the genital glands contains irregular plates and spicules 

 of various sizes, which are not in contact with each other. 



The tentacles contain niunerous spicules in the proximal portion. 



Comatula rotalaria. — Along the ambulacral grooves, with their rounded ends 

 filling the inner ends of the ambulacral lappets and their pointed ends toward the 

 pinnulars, is a series of thin, but well and definitely formed, pumpkin-seed shaped 

 plates, about four to each pinnular; between these and the pinnulars the lateral 

 perisome of the pinnules is occupied by a very loose irregular network of long and 

 slender spicules, which may toward the distal end of the pinnules broaden into 

 irregular films several meshes wide; at the distal end of the pinnules the pumpkin- 

 seed shaped plates reach downward to the pinnulars. 



Comatula Solaris. — The ambulacral lappets are occupied by thin and filmy, but 

 large and very definite, pumpkin-seed shaped plates, of which there are about four 

 to a pinnular; between each of these and the pinnulars is a very narrow and 

 irregular side plate standing at right angles to the pinnulars, on the outer end of 

 which the point of the covering plate rests, which is sometimes resolved into a more 

 or less loose mass of spicules. 



Comatula pectinata. — In the middle of the free portion of each of the am- 

 bulacral lappets is a small plate with unfinished borders, composed of from 6 to 12 

 hexagonal meshes. The lateral perisome of the pinnules between the ambulacral 

 lappets and the pinnulars contains only minute spicules. 



In the tentacles spicules are verj' rare or entirely absent. 



Comactinia 7neridionalis. — The ambulacral lappets in a specimen from Yucatan 

 are occupied by extremelj' thin and filmy plates, which may be of considerable size, 

 though always irregular, completely filling them, or may be narrowed to a long, 

 narrow, calcareous band from one to three meslies wide standing at right angles to 

 the pinnulars. 



In a specimen from South Carolina the ambulacral lappets contain a small 

 group of spicules, which at the most form one or two meshes ; between each of these 

 and the border of the pinnulars is another, usually smaller, group of spicules; in 

 some cases the two together may form merely a straight or irregular line or band of 

 scattered spicules reaching from the lappet to the pinnulars. 



There appear to be no deposits in the tentacles. 



Comatulides australis. — There are no deposits in the ventral perisome of the 

 pinnules, and none in the tentacles. 



Comaster novwg-uinea'. — The lateral perisome of the pinnules contains nu- 

 merous large straight or branched spicules, which may form a continuous closely-set 

 row along the margins of the pinnulars, with which they make a right angle, may 

 form a loose spiculiferous band which is continued into the lappets, or may be col- 

 lected in little groups, two or three groups to a pinnular. 



