248 BULLETIN 201, UNITED STATES NATIONAL MUSEUM 



NEOMYSIS MONTICELLI Colosi 



Neomysis monticelli Colosi, 1924, p. 6, figs. 7-9. 



Distribution. — Known only from the original record of Colosi from 

 the Strait of Magellan*. 



ACANTHOMYSIS SCULPTA (Tattersall) 



Figures 83-85 

 Neomysis sculpt a Tattersall, 1933, p. 17, figs. 9-11. 



Distribution. — This species has so far been collected only on the 

 coast of British Columbia. 



Remarks. — This species may be recognized by the following 

 characters : 



(1) The somites of the pleon (fig. 83, a, b) are furnished with trans- 

 verse ridges, which represent folds of the integument and give the 

 impression that the somite is subdivided into subsidiary segments. 

 There are three ridges on the first somite and two on each of the suc- 

 ceeding somites. The fourth abdominal somite has a posterior dorsal 

 median spine. The fifth somite has a similar spine but in addition 

 a prominent lateral spine on each side. The sixth abdominal somite 

 has a median dorsal spine and, in addition, is furnished with an 

 anterior median blunt plate and a posterior pair of blunt spines, with 

 grooves and carinae. 



(2) The carapace is produced in front into a short triangular 

 rostral plate with a pointed apex; the anterolateral corners are 

 rounded. 



(3) The eyes (fig. 84, a) are large and prominent, pigment black, 

 one and a third times as long as broad, cornea occupying about half 

 of the eye. 



(4) Antennal scale (fig. 84, b) is six times as long as broad with a 

 distinct distal segment. The scale extends beyond the antennular 

 peduncle for about one-third of its length. 



(5) The endopods (fig. 85, a) of the third to the eighth thoracic 

 limbs have the sixth joint divided into 7 or 8 subjoints. 



(6) The telson (fig. 84, d) is linguiform, about three times as long 

 as broad at the base. The apex is narrowly truncate and armed with 

 two pairs of spines, the inner pair of which is longer than the outer. 

 The lateral margins are armed throughout their length with about 50 

 spines, which, on the distal two-thirds of the margin, are arranged 

 in groups of from 2 to 10 small spines between the larger spines. 



(7) The inner uropod (fig. 85, b) has a group of seven spines on 

 the inner margin near the statocyst. 



(8) The fourth pleopod of the male (fig. 84, c) has the proximal 

 joint of the exopod twice as long as the distal. The terminal setae 



