194 BULLETIN OF THE 
Family CALOCARIDZ. 
CALASTACUS, gen. nov. 
Abdomen long, enlarged in the middle, narrowed at each extremity, pleure 
broad and rounded. Cephalothorax laterally compressed, rostrum long, acute ; 
eyes rudimentary, subglobose, unpigmented, unfaceted. Second antenna on 
a horizontal line with the first antenna; the second segment armed with a 
long external spine (stylocerite) and a still longer articulated style-shaped 
scale (scaphocerite). Third maxilliped pediform. First and second pairs of 
legs chelate. First abdominal appendages of male modified to serve as sexual 
organs (gonopods). Outer branch of swimmerets divided near the posterior 
margin by a diagonal suture. Telson long, quadrangular. Gills composed of 
a central stem which bears two rows of filaments. Branchial formula : 
Somite VATE LX Xe Xa See Xa Te Relive: 
Epipods:, 2.) 31/24) 4 1 1 1 1 1 0696 
Podobranchie. . O 1 i 1 1 0 Oo = 4 
Arthrobranchie . 0O 2 2 Z 2 2 0 =10 
Pleurobranchie . 0 0 0 0 0 0 Oo = 0 
Differs from Calocaris in having a long styloid scaphocerite appended to the 
peduncle of the externa] antenne. 
Calastacus stilirostris, sp. nov. 
Carapace naked, punctate ; apex of rostrum turned a little upward; two 
strong spines turned upward and forward at base of rostrum ; a light median 
carina runs along the back from the base of the rostrum, fading out before 
reaching the hind border of the carapace. Chelipeds Jong, symmetrical on the 
two sides ; coxa furnished with a small spine on the anterior border of the dis- 
tal end ; ischium armed with from one to four spines on the lower margin ; 
merus laterally compressed, armed with a spine on the upper edge near the 
distal end and a variable number (four to eight) of spines on the lower edge. 
Carpus triangular, unarmed. Chela: upper and lower margins sharp, the 
upper armed with five to seven spines, inner and outer faces with a few scat- 
tered spinules; fingers with denticulate prehensile edges and curved crossed 
extremities. Second pair of legs furnished with small chele. 
Length of carapace, 22.2 mm.; rostrum, 5.56 mm.; abdomen, 30 mm. ; 
cheliped, 39 mm. ; chela, 17 mm. 
Station 3418. 660 fathoms. 9 males. ° 
