no. 1136. OBSERVATIONS ON THE ASTACIDJE— FAXON. 687 



row of confluescent pits, outer face with a longitudinal furrow just 

 below the superior margin; cutting edges of the fingers armed with a 

 few blunt teeth near the proximal end. The inner branch of the last 

 pair of abdominal appendages bears a longitudinal median rib, which 

 runs nearly to the posterior margin of the segment, but this rib does 

 not end in a spine as it usually does in the crayfishes. 



Length 47 mm.; length of carapace 23.5 mm.; from tip of rostrum 

 to cervical groove 15 mm.; from cervical groove to hind border of 

 carapace 9.3 mm.; breadth of areola 1.75 mm.; length of cheliped 31 

 mm.; length of merus 9 mm.; length of carpus 6 mm.; breadth of 

 carpus 6 mm.; length of chela 13.5 mm.; breadth of chela 8 mm.; 

 superior margin of propodite 6.2 mm.; length of dactylus 8 mm. 



Habitat— Montevideo, Uruguay. W. E. Safford, IT. S. S. " Vaudalia." 

 (Coll. U.S.jST.M.) Three specimens. Taken, together with P. saffordi, 

 in burrows two meters deep, one hundred meters from the coast, in 

 strata of sand covered by soil. 



Parastacus defossus is a species whose appearance clearly reveals its 

 subterranean mode of life, like Gambartis diogenes of the United States 

 and the so called JEJngcei of Tasmania. It has some affinity with P. 

 brasiliensis of southern Brazil, a species not especially fossorial in 

 habit, but found in brooks and springs. P. defossus is easily distin- 

 guished from P. brasiliensis by the extreme lateral compression of the 

 cephalo-thorax, the small size of the anterior end of the abdomen, the 

 strong convergence of the lateral margins of the rostrum, the length 

 and narrowness of the areola, the shape of the chela (which is much 

 shorter and broader than in P. brasiliensis), the long oval outline of 

 the telson, etc. 



PARASTACUS HASSLERI, new species. 



(Plate LXX, figs. 1-3.) 



Cephalo-thorax narrow. Eostrum rather short, reaching nearly to 

 the distal end of the second segment of the antennular peduncle; upper 

 surface slightly excavated, with raised, toothless margins convergent 

 from the base to the blunt (sometimes truncate) extremity. Postorbital 

 ridges slightly marked, strongly divergent from before backward, not 

 confluent with the margins of the rostrum, inflated at the posterior end 

 so as to form a low tubercle. Wall of the orbit produced to form a prom- 

 inent angle under the eye, but not armed with a spine. Dorsal surface 

 of carapace smooth, polished, nearly free from impressed dots over the 

 gastric area, areola rather narrow, its field thickly strewn with im- 

 pressed dots; a group of six to nine small, blunt tubercles on the ante- 

 rior part of the lateral walls of the carapace; branchial regions lightly 

 granular. Distance from tip of rostrum to cervical groove about twice 

 the length of the areola. Abdominal pleurce rounded. Hind border 

 of telson rounded, lateral spines obsolescent. Anterior process of epis- 



