ISOPODS OK NORTH AMKRICA. 0V)7 



A])donion not iibruptly iiiinowcr than the thorax; cpiniera hirge, dis- 

 tant; terminal segment truncate. 



Lateral parts of the thora(;ic seg'ments <>x})anded, discontinuous. 



Inner branch of tlie first pair of pleopods in tlie mah>, produced, 

 hiarticulate, that of the second pair in the male triarticulate. Inner 

 branch of the uropoda tertninatino- in a sinole, slender spine: basal 

 article broadly expanded inside. 



Legs rather short and thici<. scarcely increasing in length posteriorly. 



HAPLOPHTHALMUS PUTEUS Hay. 



Haplophthalmus puteiis Hay, Troc. U. S. Nat. Mus., XXI, 1899, pji. 871-872, pi. 

 Lxxxvi, figs. 1-15. 



Localities. — Wells in Indiana. 



^''Male. — Body elliptical, length about three times the breadth, dor- 

 sal surface strongly convex, covered with longitudinal rows of low 

 tu))ercles and scattered seta\ Segments of the perjvon about equal in 

 length, the ])osterior pleural angle of all, except the first, more or less 

 produced l>ack\vard. Pleune of third, fourth, and fifth segments of 

 the })leon thin and directed backward and outward. Terminal seg- 

 ment of al)domen notched behind and with the postero-lateral margins 

 concave. Uropods exscrted, short, outer lamus longer than inner; 

 ])()th rami setose. Front margin of head very slightly pi'oduced. 

 Antenna' longer than the greatest breadth of the body; first and sec- 

 ond segments of medium length, third short, fourth and fifth long; 

 flagellum short, pinniform, composed of three very small, closely 

 articulated segments. Antemue genicidatc between segments four 

 and five. Antennules minute, composed of three segments entirel}' 

 concealed ])y the front of the head, sensory filaments five. Eyes 

 small, simple. Upper lip regularly rounded in fi'ont and with a 

 UKHlian triangular })atch of setie. Mandibles large and powerful, 

 bearing on the inner surface a broad, ridged molar tul)ercle; on the 

 anterior sui-face, one or two delicate, branched sensory styles. The 

 cutting portion of the mandibles is different; that on the left consists 

 of two portions, an outer with four heavy teeth and an inner with 

 three much smaller teeth; the outer mandible has l)ut one row of 

 three or four large teeth which, when (dosed, lit in the space between 

 the two rows of teeth of the mandilde first described. The first max- 

 illa has both branches erect, the outer bearing five or six acute curved 

 teeth, the inner three delicate plumose flagelliform processes. The 

 second maxilla consists of two strap-sha})ed lamelhe closely applied to 

 one another and bearing seta' at their ends. The maxilliped is a 

 broad, low, flattened plate, with straight inner and rounded outer 

 margins, and bearing at the tip two obscurely segmented setose proc- 



