300 bulletin: museum of comparative zoology. 



h Oral papillae narrow and elongated; under arm-plates 



transversely ellipsoidal; no blue affinis 



h' Oral papillae wide, nearly circular; under arm-plates 



squarish or pentagonal ; more or less blue cyanosticta 



/' Disk-scales much finer, 7-11 series in each interbrachial area; 

 oral shields distinctly longer than wide; under arm-plates 

 widely in contact, broader than long. 



g Interbrachial areas below nearly naked; oral shields bud- 

 or acorn-shaped ; adoral plates meeting radially . qtuidrispina 

 g' Interbrachial areas below covered with plates; oral shields 

 spearhead-shaped; adoral plates not meeting radially 



conferta 

 d' Radial shields small, their length about -J radius of disk or even less. 

 e Arm-spines 4 or 5; disk-scaling not very coarse, 6 series or more 

 in each interbrachial area; usually (perhaps always) 5 arms. 

 / Disk-scaling fine, 11-15 series in each interbrachial area. cornea 

 /' Disk-scaUng coarser, 6-9 series in each interbrachial area. 

 g Numerous spines in interbrachial areas below; under arm- 

 plates somewhat quadrilateral, wider than long . . . africana 

 g' No spines in interbrachial areas; under arm-plates at base of 

 arm somewhat triangular, soon becoming more or less 



circular lutkeni 



e' Arm-spines 3 or 4; disk-scaling coarse, about 5 series in each 

 interbrachial area; usually 6 arms. 

 / Radial shields exceedingly small, no larger than some of the 



disk-plates virens 



f Radial shields moderate, larger than any disk-plates. 



g Spinelets present in interbrachial areas at least below; under 



arm-plates as wide as long or wider arenosa 



g' Spinelets lacking; under arm-plates longer than wide. 



brachyaspis 

 c' 2 oral papillae on each side of each jaw. 



d 7 arms; radial shields short and well-separated hirta 



d' 5 or 6 arms. 



e Arm-spines long, middle ones much exceeding segment and 

 usually equalling or exceeding arm width; disk-scaling coarse; 

 disk-spines numerous all over body in adults but lacking on 



upper surface of disk in young asperula 



e' Not as above. 

 / Arm-spines 7 or 8, upper ones very slender and pointed, much 



shorter than segment hemiteles 



f Arm-spines usually 4 or 5, rarely more and then in very large 

 specimens, stout and blunt or bluntly pointed. 

 g Disk-scales coarse about 5 series in each interbrachial area 

 where narrowest; these areas below, more or less naked in 

 adults. 



