196 CARL BOVALLIUS, AMPHIPODA HYPER1IDEA. I 2. HYPERIID^E. 



Hyperia agilis. 



Syn. 1852. Hyperia agilis, J. D. DANA. — United States Exploring Expedition. Crusta- 



cea. Vol. 2, p. 986, pi. 67, fig. 11a— lid- 



» » » Spence Bate. 1862. Catal. Amph. Crust. Brit. Museum, p. 296, 



pi. 49, fig. 3. 



» » » C. Bovallius. 1887. "Systematical list of the Amphipoda Hy- 



periidea.» Bih. t. K. Sv. Vet. Ak. Handl. 

 Bd. 11. N:o 16, p. 17. 



I have not met with any specimen of this species in the collections which I have 

 examined hitherto, but judging from the description and the drawings given by Dana I 

 believe that it may be a good species. Spence Bate says in 1862 that the description of 

 Dana »so closely resembles that of Lestrigonus Gaud who udii, that I should have united 

 them, had not Dana described the flagella of this species as being uniarticulate». 



For that reason I for my part should not hesitate to unite them if the other charac- 

 teristics agreed, the less so because Dana in his diagnosis expressly says ^articulo ultimo 



interdum obsolete articulator. But, as may be seen from the above diagnosis, there 



are other distinctions between the two species as for instance, the narrow femur of the 

 first two pairs of peraeopoda, the relation between the length of the two first pairs and 

 the third and fourth pairs, and between the length of these last and the fifth, sixth, and 

 seventh pairs, etc. 



The Latin diagnosis of Dana runs: 



»Caput mediocre, pigmentis oculorum angustis. Thorax longus, epimeris totis brevibus, 

 truncatis. Antennas longiuscula?, dimidii thoracis longitudine subaequae; 2d<B parce longiores, 3- 

 articulatae, non teretes, articulo ultimo longo et remote pubescente, interdum obsolete articulato; 

 lmse 5-articulatae, articulo 4to crasso longoque et infra ciliato, ultimo minuto. Pedes 4 antici 

 subasqui, coxis angustis; 6 postici mediocres; setis brevibus et paucis.» 



From the short description of Dana I give the following details: 



In front view of the head, the antennary area is large, nearly square, and the pigment 

 occupies nearly all the space on the side of it. 



"Pigment of eyes much smaller than usual, black. 



Antennae rather long (half as long as thorax), subequal; superior five-jointed, fourth joint 

 stout, long, ciliate below, the last minute; inferior slightly the longest, three-jointed, not terete, 

 last joint long, and remotely hairy. — — 



The inferior antennas have two short basal joints, and then a long, compressed, subulate 

 joint, which is a little hairy. 



Thorax long, all the epimerals short, truncate. The seven thoracic segments about equal. 



The four anterior legs have the last three joints, or the terminal portion straight, and 

 apparently admitting of upward flexion alone; they terminate in a nearly straight spine. Four 

 anterior feet subequal, coxas narrow. Six posterior of moderate length, seta? short and few. 



First three abdominal segments with the posterior angle on either side of each, prominent 

 and acute. 



While swimming, the legs are generally folded up across the venter; it swims by means 

 of the abdominal legs, and the extremity of the abdomen." 



