270 ART, 2. — H. MATSUMOTO : 



lowest one shortest, the former being as long as, or longer than, 



the corresponding arm joint leptodenia. 



AA. — Genital papilla3 and comb papillne squarish, flat, short, blunt, close- 

 set ; second oral tentacle pore opening nearly or entirely outside the 

 oral slit ; arms cylindrical, about as wide as high at the base ; arm 

 spines minute, short irrorata-^xoxv^ (HI)- 



h. — Disk scales naked ; arm spines well spaced. 

 i. — Three arm spines. 



j. — The two sets of comb papillte on the sides of an arm base not 

 continuous ; oral shields much wider than long. 



k. — Oral shields wider without than within ; arm spines minute, sub- 

 equal ; tentacle scales very numerous, twelve to fifteen to the second 

 oral tentacle pore, eight to eleven to the first tentacle pore, five to 

 eight to the second tentacle pore, &c irrorata. 



Mc. — Oral shields wider within than without ; arm spines not very 

 minute, uppermost one longest and lowest one shortest ; tentacle 

 scales rather few, eight or uine to the second oral tentacle pore, 

 four or five to the first tentacle pore, three or four to the second 

 tentacle pore, and one or two to those beyond paucisqiiama. 



jj. — The two sets of comb x^apillas on the sides of an arm base form- 

 ing a single unbroken series ; oral shields about as wide as long, 



wider within than without; arm spines sube(]ual ononostœcha. 



a. — Six arm spines, minute, peg-like, sube(]ual, evenly spaced ; disk 

 scales thin and hard to distinguish ; oral shields pentagonal, slightly 

 longer than wide albata. 



Jill. — Disk covered by a thick, soft skin, which obscures the underlying 

 scales ; arm spines closely set. 

 I. — Six or seven arm spines ; disk scales rather coarse and thick, 

 radial shields present ; arm combs rudimentary or entirely absent . . 



calyptolepis, 



II. — Seven to nine arm spines; disk scales and radial shields almost 



aborted in adult specimens ; arm combs well developed 



cryptolepis. 



