268 Bvlletin Vander-bilt Marine Museum, Vol. VII 



Seven exceptionally large specimens, from the above-cited local- 

 ity. Fifty-two specimens, mostly very large specimens, from the 

 identical locality. Twenty-four specimens, of medium and small 

 size, dredged in 9 fathoms, at Port Lagunas, Chile, February 13, 

 1935. Five specimens, of medium and small size, dredged in 

 Chiquiso Channel, between Chiloe and Cailin Islands, Chiloe 

 Archipelago, Chile, in 7 fathoms. 



Discussion : Although this species was previously taken by 

 the "Ara," in 100 fathoms, Punta Arenas, Costa Rica, and de- 

 scribed in Volume III, Bulletin of the Vanderbilt Marine Museum, 

 p. 53, plate 12, the present Chilean series is of such exceptional 

 vialue, both in extent and source, that it is desirable to present 

 the following notes. The description is based on an average 

 large specimen taken in the Ton Gay Peninsula dredgings, sup- 

 plemented, at the conclusion, by a comparative analysis of a series 

 of sixty-three specimens, showing the percentage of variation 

 existent, especially in the number and arrangement of spines 

 ornamenting the carapace and abdominal somites. 



Technical description: Carapace subrectangular, pro- 

 duced anteriorly to a slender acuminate rostral spine, which is 

 subequal in length to the precervical portion of the carapace and 

 is very compressed laterally, with the lateral margin finely cari- 

 nate and the dorsal margin crested and denticulate, this crest 

 originating as a non-denticulate carina extending briefly on the 

 carapace, continuing forward on the rostrum, bearing six or 

 seven compressed, forward and upward-directed teeth which nor- 

 mally increase in size from proximal to subdistal, this tooth 

 being situated about two-thirds of the length of the r6strum, at 

 the apex of the crest, beyond which the dorsal margin of the ros- 

 trum is concavely deflected to the apex. The inferior rostral mar- 

 gin usually, but not always, bears one strong obliquely downward 

 and forward directed tooth, approximately opposite or slightly in 

 advance of the large subdistal tooth of the dorsal series, this in- 

 ferior spine being slightly in advance of the eye. There are a 

 pair of short acuminate preorbital spines, one on either side ad- 

 jacent to the base of the rostrum, another pair of subequal or 

 sometimes slightly shorter spines occur, one each above the base 

 of the antennae. The precervical portion of the carapace bears 

 anteriorly about five unbroken transverse carinae and immedi- 



