210 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



B^. Knob not prominent, unarmed. 



Accessory carinae never spined, very rarely with even a small 

 nodulation or two. Submedian crests usually armed with one spine or 

 spinule, sometimes 2, rarely unarmed and then on one side only. Ocu- 

 lar plates more or less squarish, anterolateral angles somewhat pro- 

 duced anteriorly in some specimens, but never so markedly as in 

 G. bahiahondensis. Anterolateral angles of the rostral plate produced, 

 subacute, but never spiniform stanschi, p. 215 



B2. Knob usually armed with at least one pair of small spines or spin- 

 ules (see also under C^ below on this point). 



Accessory carinae usually armed, at least in larger specimens, with 

 one or more spines or spinules. 



G^. Knob armed with no more than 2 spines or spinules, only 

 rarely and in small specimens may these be replaced by 

 small nodules or tubercles; very rarely is there an extra, 

 apparently adventitious, spinule on the knob of this species. 



Accessory carinae usually armed with one or 2, rarely 3, spines 

 and then on one side only; very rarely unarmed; may be un- 

 armed, in small specimens. Crests of submedian teeth usually 

 armed with one or two spines. Intermediate carinae usually end 

 in a posterior spine or spinule, usually followed by a second small 

 spinule in line behind it; rarely is the second of the 2 spinules 

 represented by a small bead or nodule, much more rarely does one 

 find both so replaced. Ocular plates have anterolateral angles 

 produced anteriorly; not appearing wider than long. Antero- 

 lateral angles of the rostral plate almost always spiniform. . . . 

 bahiahondensis, p. 217 



C^. Knob typically, and usually, armed with more than 2 spi- 

 nules, very exceptionally armed with only 2, in such cases 

 there are one or two nodules or small tubercles in addition. 



Accessory carinae armed with 3 or more spinules, rarely only 2. 

 Intermediate carinae with several spinules in patch at or just be- 

 hind posterior extremity; very exceptionally in small specimens 

 are there only 2 spinules so placed. 



D^. Submedian carinae more or less merged posteriorly with 

 median carina to form an anchor posteriorly or, as one 

 might say, a coronet ornamented with from 3, usually 

 more, up to 8 spinules. 



Klnob also forming a coronet of usually 4 to 6 backwardly di- 

 rected spinules, rarely only 3, sometimes as many as 7. Acces- 



