62 U.S. NATIONAL MUSEUM BULLETIN 260 



Ocean. The shape of coxa 6 is a remarkable characteristic of 0. 'pin- 

 guis. The condition of coxa 6 is known in many other species of 

 Orchomene {^ Orchomenopsis Sars, Orchomenella Sars, fAllogaussia 

 Schellenberg) but so far only O. minuta (Kr0yer) has been shown to 

 have a shape almost precisely similar to that of 0. pinguis (see Gur- 

 janova,1962,fig.41). 



Orchomene minuta differs from 0. pinguis in the stronger lobation 

 of the epistome and the unexpanded coxa 1. 



The question arises as to whether the Califomian population should 

 be distinguished nomenclaturally from that of Woods Hole ; indeed, 

 one wonders whether that from Woods Hole differs minutely from that 

 of the eastern Atlantic. The genus is very diverse and many species 

 are distinguished from one another by weakly developed characters, 

 some of less magnitude than seen in the two populations analyzed 

 here. For instance, Gurjanova (1962) has arranged 0. m^inuta^ 0, 

 lepidula (new species), 0. intermedia (new species), 0. minuscula 

 (new species) , and 0. pinguis in consecutive order to demonstrate their 

 close affinities. She shows three varieties of 0. minuta^ two of 0. in- 

 termedia and two of 0. pinguis besides. Tliese nine species and vari- 

 ants are, in general, distinguished from each other in no more remark- 

 able ways than are the two populations described herein. Table 3 

 has been composed by utilizing six characters to distinguish the nine 

 '"variants" of Gurjanova plus the California and Woods Hole popu- 

 lations. Numerous other characters could be so treated. One can 

 almost imagine an infinite variety of potential combinations of 

 characters. 



If all known characters are considered the California population 

 stands closest to that of 0. pinguis figured by Gurjanova except in 

 three gross characters, the broader lobe of article 5 on gnathopod 1, 

 the larger eyes (?) and the enlarged and falconiform article 6 of 

 gnathopod 2. Gnathopod 1 and eyes of Californian specimens resem- 

 ble those of 0. minuscula but coxa 6 of that species is only weakly 

 elongated and the posterior lobe weakly quadrate. Coxa 4 of 6>. minus- 

 cula has a broader posterior lobe. The Californian specimens are 

 clearly different from 0. minuta in epistome, coxa 1, and gnathopod 2 ; 

 from one population of O. minuta in epimeron 2 but not gnathopod 2 ; 

 and from another population in gnathopod 2 but not gnathopod 1. 

 Coxa 6 and epistome are clearly distinct in 0. lepidula. Orchomene 

 intermedia is truly w^hat its name suggests, because coxa 6 is almost 

 fully like that of O. pinguis^ gnathopod 1 is intermediate between that 

 of 0. minuscida and O. pinguis^ the epistome is only moderately lobate, 

 the cephalic lobes are very sharp, eyes are apparently large, and coxa 

 5 has an enlarged posterior lobe. In summary the Californian speci- 



