1 -II 



• ■ dorsal porrion of the 1ms.i1 segments of Pd is visible between the [IBr series. 

 The dorsal profile i>t' the arms is smooth. 



\ similar specimen has 2S arms; eight of the IIBr series are 4(3 | 4) and two are 2; 

 the cirri are frora 25 mm. to ; v j mm. long with 20- 23 segments. 



rhe remaining three examples are small, with 20. ig and 17 arms. 



3. ( 'ptentrionalis \. II. Clark). 



.\. II. Clark. Proc. U.S. National Museum, vol. 34, 1908, p. ,12 [Charitometra distincta). 

 tional Museum, vol. 39, 191 1, 554 [Pachylometra se ptentrionalis). 



Perissometra \. II. Clark. 



Key t<> the Species of the Genus Perissometra. 



'roximal portion of the animal abruptly constricted, the sides of the [Br 



seen in lateral view, being nearly parallel, but the sides of the IIBr 



and arm bases divergent; 14 — 20 arms 75 mm. long; IIBr | 3 +4); 



cirri XX XXV, iS — 23, all, or most, of the segments longer than broad 



Meangis Islands; 900 Metres) angusticalyx 



onstriction of the proximal portion of the animal 

 li' 14 — 20 (usually 20) arms 



c 1 IIBr 2; rather slender; cirri with all of the component segments longer 

 than broad 



d 1 ossicles of the division series and brachials each with a broad low 

 inconspicuous median keel which persists to the end of the arms; 

 distal edges of the discoidal brachials bevond the second prominently 

 and abruptly everted, of the more distal triangular brachials produced 

 and overlapping; arms 14 — 20, 170 mm. to 175 mm. long; cirri 

 rather short and wr;ik. XX — XXX, 17 — 22, 30 mm. to 37 mm. 

 long S a h u 1 Bank and the Kei Islands t o t h e Philip- 



pines; 104 1 |.o Metres) patuia 



d ossicles of the division series with the dorsal surface unmodified, or 

 with a more or less d<-veloped broad rounded tubercle; no eversion 

 of the distal borders of the brachials; 12 — 16 arms 250 mm. long; 

 cirri very long and stout. XX — L, iS — 3] (usually 28—31) 55111111. 

 to 70 mm. long (Sahul Bank and Timor to the Kei Islands; 



2^2 — 5 20 Me t r e s) rooit s/a 



IIBr 1 ; \ . stout: ossicles of the division series and brachials each 

 with a low median rounded tubercle which becomes obsolete in the 



.u of the arms 

 d' brachials with smooth and unmodified distal edges and a slightly 

 orsal surfaee; profile oi the division series and arm bases 

 divi it an angle of slightly less than 90 ; arms 205111111. long; 



