146 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



Whereas the extreme of slenderness in the oral pinnules is seen in the Ante- 

 donidEe, in such genera as Trichometra and H athrometra (fig. 289, p. 221), the 

 maximum stoutness is found in Himerometra (figs. 270, p. 207. and 326, p. 227), 



The large species of the 

 genus Zygonietra have oral 

 pinnules corresponding very 

 closely with those of the 

 species of IlimeromMra; but 

 the pinnules taj^er distally to 

 a more slender tip than is 

 usually found in that genus, 

 though such a tip occurs in 

 //. fers'ica (fig. 272, p. 207) 

 and in H. hartschl. In Ca- 

 toptonietra the structure of 

 the proximal pinnules is very 

 similar to that of the proxi- 

 mal pinnules of the species of 

 Comasteridse, though there 

 are no terminal combs. In 

 Kudiocrimts (figs. 190, p. 

 Ill; 191, p. 112; and part 1, 

 figs. 83. p. 136, and 84, p. 

 137) the oral pinnules are 

 very stout and sharph^ pris- 

 matic, recalling i*^ in certain 

 of the Thalassometrinse. 



In the genus Pontiojnetra 

 (fig. 277, p. 213), belonging 

 to the Mariametridae, Pj is, 

 strictly speaking, the only 

 oral pinnule. It is nearly 

 eight times as long as the fol- 

 lowing pinnules on the same 

 side of the arm, very slender, 

 with about 50 segments. P,, 

 is small, like P.. 



The species of Colobo- 

 metridse collectively are in 

 their proximal pinnule struc- 

 ture strictly comparable to 

 the si^ecies of the Himero- 

 metridas, Stephanometridse, and Mariametridro taken together, but the distal ends of 

 the segments in these pinnules are as a rule considerably more spinous than is the case 

 in these other families. In the species of OUogomefri-des, A ustrometra, and Anahido- 



FiG. 20S. — Lateral view ok specimen of Pterouetka trichopoda. 



