DECArODS 151 



CALASTACUS INVESTIGATORIS Anderson. 



Calastacus investigatoris Anderson, Jour. Asiatic Soc. Bengal, i,xv, Pt. II, 97, 

 1896. Illustrations of the Zoology of the Investigator, Crustacea, Pt. 

 IV, pi. XXV, fig. I, 1896. — Alcock, Descriptive Catal. Indian Deep-Sea 

 Crust. Dec. Macr. and Anom. in Indian Mus., 191, 1901. 



Distribution. — Taken by the Albatross, south of Sannak Islands, 

 Alaska, 483 fathoms, station 3210, i $ ; off Cascade Head, Oregon, 345 

 fathoms, station 3347, i ? ; off San Diego, California, 417 fathoms, sta- 

 tion 2928, 2 $ . 



Type locality. — Arabian Sea, off the coast of Sind, 947 fathoms 

 [Investigator). 



The antennal spines of one Califomian specimen agree with Alcock's 

 description, while in the Alaskan and Oregonian examples the scapho- 

 cerite and stylocerite are about equally produced; in the second 

 Californian specimen the stylocerite is broken ofT. There is also variability 

 in the spination of the upper margin of the merus of the large chelipeds ; 

 in one individual (from California) the whole margin is armed with spines 

 which are proximally reduced in size ; in the other three individuals ex- 

 amined only the distal half of the margin is armed, as in the types. 



CALASTACUS QUINQUESERIATUS Rathbun. 



Calastacus quinqueseriatus Rathbun, Proc. U. S. Nat. Mus., xxiv, 887, 

 1902. 



Carapace (rostrum included) measured in the middle line, as long as 

 the first 5 abdominal somites ; its surface is pitted, especially on the infero- 

 lateral portions, and a few feeble setae spring from the pits ; cervical 

 groove deep, branchial grooves indistinct. The rostrum reaches to the 

 end of the second joint of the antennular peduncle and is tipped with a 

 spine ; its lateral margins are armed with 3 to 7 spines, and the pro- 

 longations of these margins extend two thirds the length of the gastric 

 region, are armed with 5 or 6 spines, and form a horseshoe on the cara- 

 pace which is open behind and outlined in front by a groove a little 

 posterior to the orbit. The median carina extends from the middle of the 

 rostrum to the rear of the horseshoe and is from 2 to 6 (usually 3) spined 

 at its middle. Between the median carina and the sides of the horseshoe 

 is another row of 3 to 5 spines. The eyes are colorless and form a 

 globular tip to the short eye-stalk. 



Expanded basal portion of the first joint of the antennular peduncle 

 narrow-oval, bearing i or 2 marginal spinules near the tip. Stylo- 

 cerite of antennal peduncle reaching to distal third of the penultimate 

 joint ; scaphocerite not reaching middle of the stylocerite. The external 



