CALIGOIDEA. ^359 



is a large apron. In each of these particulars, the species differ from 

 the Trebii, although resembling them in having the posterior feet 

 two-branched and subnatatory. The species examined had no sucker 

 disks beneath the front. The furcula anterior to the first pair of nata- 

 tories was similar to the same in the Caligi. The maxillae are furcato- 

 aculeate behind, as in Trebius, and not simply aculeate, as in the 

 Caligi described. The posterior feet were more ventral in attachment 

 than usual in the Caligi. 



Calistes Teigonis. 



Feminse: — Cephalothorax subrotundatus ; segmentum secundum par vurn, 

 lateribus rotundatis. Abdomen o-articulatum, segmento prime- lato 

 subquadrato angulis rotundatis, duobus sequentibus fere cequis et simul 

 sumtis non brevioribus quam primum, linearibus, ano vix prominente. 

 Styli caudales styliformes, oblongi. Antennas postwar spina corned 

 longd extus basin munitce. Furcxda simplex, brachiis parallelis. 

 Pedes postici natatorii, ramis %-articulatis, parce subcequis, setis longis. 



Cephalothorax subrotund; second segment small, with the sides 

 rounded. Abdomen three-jointed, anterior segment very broad, 

 subquadrate, angles rounded, the following two together about same 

 length, narrow linear, two segments nearly equal ; anus scarcely 

 prominent. Caudal stylets styliform, oblong. Posterior antennse 

 having a long corneous spine exterior to base. Furcula simple, 

 with the prongs parallel. Posterior feet natatory, branches sub- 

 equal, three-jointed, setae long. 



Plate 94, fig. 7 a, ventral view of animal, enlarged ; b, posterior 

 antenna, with the exterior spine, b'; c, aculeate part of maxillae, show- 

 ing furcation; d, first pair of feetj e, second pair of feet. 



Taken from the body of a Trigon, at Kio Janeiro, December, 1838. 



Length, one-fourth of an inch. Colourless, or nearly so. 



The cephalothorax has a slight emargination in front. The first 

 abdominal segment is about half as broad as carapax. The last seg- 

 ment has a constriction near apex, which appears to indicate an obso- 





