392 PROCEEDINGS OF THE NATIONAL MUSEUM vou 80 



very low cornooiis loiobs just distad of this tubercle. Entire lateral 

 margin covered with minute denticles and scattered setae. 



Immovable finger with live low, rounded knobs along proximo- 

 mesial margin, just distad of which is a large corneous tubercle. En- 

 tire mesial margin with minute denticles. x\bout 11 small tubercles 

 on proximal lateral margin. 



Carpus about 1.6 times as long as wide; a shallow oblique groove 

 above. Punctate dorsolaterally, otherwise tuberculate. Two very 

 large tubercles anteroventrad and a rov/ of four smaller ones ventre- 

 mesad. 



Merus entirely tuberculate. Tubercles spikelike ventrad, dorsad, 

 and mesad. 



Ischiopodites of third and fourth pereiopods with strong, bitubercu- 

 latc hooks. 



First pleopod ver\^ slender and extending to base of third pereiopod; 

 tip terminating m two distinct parts. A third terminal process, the 

 mesial process, somewhat obscured by close proximity with the main 

 shaft, lies along the caudomesial margin and terminates one and one- 

 half times its own length proximad of the tip. It is spicidiform but 

 almost truncate distall3^ The cephalic process is absent, represented 

 only by a shelf on the anterodistal margin. The central projection 

 is a strongly developed, subtriangular, corneous structure which is 

 flattened laterally and extends beyond the rest of the appendage 

 distally. It is composed of two parts: the centrocaudal and the 

 centrocephalic. A caudal process arises from the caudodistal margin; 

 it is compressed laterally and is directly posterior to the central pro- 

 jection. An excavation is present mesad of the central projection 

 and caudal process. 



Male (form II). — Only slightly different from first-form male. 

 Acumen of rostrum very short, not reaching disttil end of peduncle of 

 antennule. Epistome with median spine deeply set, otherwise as in 

 the first-form male. Anterior section of telson with two spmes in left 

 posterolateral corner and one in the right. Hooks on ischiopodites 

 of third and fourth pereiopods simple and reduced. (See %. 15, c,f, k, 

 for diagrams of first pleopod.) 



In contrast to Lonnberg's desciiption (1894b, p. 6) there are very 

 small "lateral teeth" on the rostrum of my spechnens. The ridge 

 which Lonnberg speaks of as being present in "the foremost part of 

 the rostral groove" is present in one of my specimens. Occasionally 

 an extra spine is added in one or both posterolateral corners of anterior 

 section of telson. Antennae generally slightly longer than body. 

 One of my second-form males agrees perfectly with Lonnberg's de- 

 scription (i. e., proportionally) except that the areola of my specimen 

 is narrower than his; this difference holds in all my specimens. It is 

 possible that this difference is due to our measuring the width of the 



