f i 



fl 



ACANTHEPHYRA CUETIROSTKIS. 



165 



extremity of the third, fourth, fifth, and sixth segments ; the tooth on the 

 third segment is the largest, those which follow decreasing in size succes- 

 sively. The telson is equal in length to the fifth and sixth abdominal so- 

 mites combined ; it is armed with ten submarginal spines on each side. The 

 eye is dark brown, not wider than its peduncle, its proximal margin entire, 

 the ocellus wanting; the ocular peduncle is furnished with a long, blunt 

 tubercle or papilla on the inner side close to the margin of the cornea. The 

 external spines of both pairs of antenna, are short and acute ; the antennal 

 scale IS long, broad near the base, tapering distally to the small apical tooth. 

 The external branch of the swinuneret is shorter than the telson, but con- 

 siderably longer than the inner branch. 



^ Length of a male, 85 mm.; rostrum from tip to posterior dorsal tooth, 

 8.0 mm.; carapace, mcluding rostrum, 25 mm.; telson, 18.5 mm.; antennal 

 scale^ 14 mm. 



The above described form I have considered as typical, but the "Alba- 

 tross specnncns show that this species is subject to great variation. In a 

 single specimen from Station 3431 (an ovigerous female) there is a marked 

 swelhng m the median line of the gastric region ; the rostrum is not so high 



"' "" '" ^' '" ''^' ^y^'"''^^ ^«""' -I'^d ends in a longer, tapering acumen ; the 



upper margm of the rostrum is in a line with the dorsal line of the carapace 

 and the earapace is rather longer in proportion to the abdomen. The form- 

 ula for the ro.tral teeth is f This form I have catalogued as Var. a (Bate 

 ALilL, Fig. 3). 



Other specimens agree with the last in most regards, but lack the pro- 



area. The rostrum reaches to the end of the 

 antennular peduncle or a little further. The dental formula is variahle : 



T. 2^1 and f These specimens I have designated as Var. /3 (Plate XLUL, 



Jbig. 4). 



In others the rostrum is vet lontror wlfii ....i ^ ±t ± t - 



y^^ iongei, A\ith upturned acumen • the telson is 



equipped with twelve pairs of latcM^nl ^m'nna ^i i ^ i n 



, ^ ^^ iciiciai spines; tiie rostral teeth vary m num- 



at the has 





tuberance on the gastric 



ber within the limits shown in the following formula): |, |, |. 

 may be called Var. 7 (Plate XLIIL, Fig. 5). 



This form 



It will be seen on looking at the list of stations given below that the 

 typical form has a more southern distribution than the varieties. 



The extremes of variation here exhibited appear very great, but they 

 arc connected by transition forms in such a way that I am led to treat 

 them as of merely varietal importance. 



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