1903.] ; IN THE ‘CHALLENGER’ COLLECTION, 63 
he had only one. The length is 18 mm. and the locality the 
Atlantic Ocean, April 7, 1876. In a preparation bearing the 
name of the species, and besides “ Surface, 7 April, 1876, 
Atlantic,” one specimen is preserved: it must be Bate’s type, 
but it measures only 16°5 mm. in length. In Bate’s figure the 
armature on the dorsal line of the abdomen is not correct ; on 
the third segment a spine has either been broken off or is rudi- 
mentary, the base being distinct ; the spine on the fourth segment 
is only half as long as that on the fifth, shorter than in the figure, 
and directed obliquely backwards; on the sixth segment a very 
short spine is visible. The basal part of the rostrum is somewhat 
ascending, the distal spiniform and horizontally porrected. The 
ext. br. of urp. has the outer margin hairy in about § of its 
length, and the marginal tooth is very small. The distal part of 
mxp.° is very incorrectly drawn by Bate in his fig. 37; it is four- 
jointed; the third joint is short, much shorter than the fourth, 
and both together about as long as the second; the first of these 
joints terminates below in two strong setiform spines, both some- 
what longer than the second joint, which terminates in two spines 
of the same length as the preceding pair; the fourth joint 
terminates also in two spines, somewhat, but not much, shorter 
than the four just mentioned. (I cannot understand how Bate 
drew his misleading figure; it must prevent every student of 
his Report from arriving at a correct judgment.) In the British 
Museum I have drawn tolerably accurate sketches of the rostrum, 
the ext. br. of urp. and the distal part of mxp.*, and I have 
compared them with a few specimens in the Copenhagen Museum, 
previously determined and shortly described by me as the Wasti- 
gopus of S. penerinkti Bate, H. J. H.: I found the agreement to 
be so close, that I must consider JS. diapontius Bate and S. pene- 
rink Bate (the type of the latter form unfortunately is not present 
in the Museum) as two Mastigopus-stages of the same species ; 
the type of S. penerinkii Bate measured only 8 mm. in length 
and is a young Mastigopus, while S. diapontius Bate is the large 
larva. 
Bate describes S. diapontius on p. 399, S. penerinkit on p. 418; 
and the name S. diapontius must therefore be accepted for the 
species. In my earlier paper I described the black-eyed adult 
form as S. penerinkii Bate, H. J. H., but I think that jt must 
now be necessary to adopt the name JS. diapontius, not only for 
the Mastigopus, but also for the mature form, which therefore in 
the future must be named S. diapontius Bate, H. J. H. 
SERG. ARMATUS Kroyer, Bate, p. 401, pl. Ixxiii. fig. 1, 
Bate enumerates three localities: one of them is “September 
12, 1875, between Japan and Honolulu, South Pacific Ocean ” ; 
the second is “Station 256, July 21, 1875; .... north of the 
Sandwich Islands; depth 2950 fathoms.” But in the collection 
I found a statement aberrant from both, viz. : “Surface. J apan 
to Honolulu, July 1875. Type.” This bottle contained two 
