454 PROCEEmNGS OF THE NATIONAL MUSEUM vol. 9i 



specimens of this species available) at least spined or with corneous 

 granule or denticle on one or the other side of body in two specimens, 

 in a third specimen, however, on both sides ; anteroventral border of 



epimeron slightly concave to fairly straight jujuyana (p. 478) 



A?. Rostrum more or less transversely flattened"'; longitudinally troughed or 

 excavate either side of the median carina, often conspicuously so ; rostral 

 margins often thickened and appearing more or less raised or upturned; 

 rostral extremity often noticeably recurved, though sometimes straight 

 or only slightly upturned ; rostral carina sometimes fading out ante- 

 riorly before reaching tip of rostrum, sometimes also merging or fusing 

 with anterior extremity of rostrum to the more or less complete oblitera- 

 tion of carina and the scales with which it may be furnished, corneous 

 scales sometimes continued to tip of rostrum as a feeble, scattered line of 

 scales only ; front of species in this section of key relatively narrow, at 

 least in appearance, as compared with species of A^ section, p. 451 ; 

 orbital spines usually snjall, often placed rather close to and sometimes 

 apparently even up the inner slope or margin of anterolateral spine, 

 or wanting altogether. 

 B\ Carapace prominently keeled or carinated for its entire length; rostral 

 carina anteriorly fading out in distal third of free portion of rostrum, 

 merging with its thickened distal extremity; lateral margin of pos- 

 terior portion of carapace (behind cervical groove) conspicuously 

 serrate, sharply notched, and armed with prominent sawteeth or 

 flattened triangular spinelike teeth ; orbital spine of good size ; extra- 

 orbital sinus well formed, a prominent feature of the front, though 

 moderately narrow, being perhaps no more than one-fourth width of 

 orbital sinus ; anterolateral spines attaining one-third to one-fourth 

 length of cornea ; palmar crest thick, conspicuously spined ; movable 

 finger with a sharply spined acute lobe on outer margin near base; 

 dorsal anterior angle of second (in lateral view, apparent first) 

 epimeron produced to form an acute corneous tipped spine. 



denticulata (p. 480) 

 B". Except for rostral carina, which may run backward as far as level of 

 anterior margins of protogastric lobes, carapace not noticeably if at 

 all keeled; lateral margins of posterior portion of carapace (behind 

 cervical groove) at most small spinulate or small corneous spined and 

 not at all toothed except perhaps for notch at lateral extremity of 

 cervical groove and at end of suture line immediately behind lateral 

 terminus of cervical groove. 

 C\ Anterior third, or even nearly half in some cases, of upper surface of 

 free portion of rostrum gently excavate or concave from side to side 

 with usually no more than trace of forward extension of rostral 

 carina or scales with which its carina is furnished; distal portion 

 of rostrum typically and usually strongly and more or less abruptly 

 recurved ; rostral outline moderately broad triangular, carina short 

 but well marked, furnished with a single row of irregularly alter- 

 nating corneous scales; orbital spine may or may not be developed; 

 nearly always, however, a slight, sometimes abrupt, but always 

 narrow offset between outer end of orbital margin and inner slope 

 or margin of anterolateral spine; this offset about as often without 



" In lateral view at the level of the anterior margin of the cornea, the dorsal height of 

 the rostrum, or its carina, above the lateral margin of the rostrum is usually much less 

 than the depth of the rostrum below the lateral margin. 



