546 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



the dorsal surface and distal edges are rough. P 2 is 3 mm. long, with 10 segments, of 

 which all but the first are longer than broad, the fourth and following twice as long as 

 broad. P 3 , the first genital pinnule, is about 3 mm. long with 10 to 12 segments and 

 has an ambulacral furrow; the first two segments are short, the third to seventh, along 

 which the testis (the specimen is a male) lies, are considerably longer and are slightly 

 expanded, the third is as long as broad, the fourth is as broad but slightly longer, the 

 fifth is not so broad as the fourth and is longer than broad, the sixth is narrower and 

 about twice as long as broad, the seventh is more than twice as long as broad, and the 

 remainder are narrow and elongated, about three tunes as long as broad. All the 

 segments have strongly everted and spinous distal edges; the spines are strongest on 

 the aboral edges of the expanded segments. 



The genital pinnules extend to P 18 . They resemble P 3 except that the expansion 

 along which the testis lies gradually lessens, disappearing at about P 10 . The genital 

 pinnules gradually increase in length and in the number of segments. P 4 is 3,5 mm. 

 long, with 10 segments; P !0 is 4.5 mm. long, with 13 segments; Pi 8 is 5 mm. long, with 

 14 segments. On the adoral side of each testis opposite the third segment of the geni- 

 tal pinnule there is a small papilla, through which presumably the spermatozoa pass 

 to the outside. The distal pinnules are composed of 17 segments, all but the first two 

 of which are two or three tunes as long as broad; all the segments have everted and 

 spinous distal edges. 



There are reduced rodlike side plates along the pinnule ambulacra. These may 

 be simple smooth rods, or they may be knobbed, or have branched or reticulated ends. 

 There are no spicules in the tentacles. 



Sacculi are very numerous and conspicuous, regularly arranged along the pinnule 

 ambulacra. 



Locality. Discovery Investigations station 1948; east of Clarence Island (N.E. of 

 the tip of Graham Land) (lat. 6049'24" S., long. 5240' W.) ; 490-610 meters; January 

 4, 1937 [John, 1938] (1, B.M.). 



History. This species was described by Dr. D. Dilwyn John in 1938 from one male 

 specimen and part of another dredged by the Discovery Investigations in 1937. He 

 said that it differs from the other species of Eumorphometra by having the cirrus sockets 

 arranged in two or three alternating rows instead of in columns, by the fact that PI is 

 not only longer but much more massive than P 2 and by the slight expansion of the 

 segments of the lower genital pinnules which carry the gonads. 



[NOTE BY A.M.C.] Mr. Clark concluded from this that E. marri should be re- 

 ferred to the Bathymetrinae and more particularly to the genus Isometra, which he in- 

 cluded in that subfamily. On paper this appears to be a reasonable move but an exami- 

 nation of the holotype of marri and a direct comparison with the species of Isometra 

 and with the other material of Eumorphometra in the British Museum has convinced 

 me that the original position of marri is more likely to be the correct one. The expan- 

 sion of the segments of the genital pinnules is very slight compared with its develop- 

 ment in Isometra even for a male, and despite the small size the specimen appears to be 

 mature. The irregularity in position of the cirrus sockets is only a little more evident 

 than in the other species of Eumorphometra and the brachials and pinnule segments are 

 much more flared and spinous at their distal ends than in any specimen of Isometra I 

 have seen. 



