NO. 1136. OBSEBVATIONS ON THE ASTAClDJi— FAXON. 683 



three females (Coll. Mus. Corap. Zool. and Coll. Dunedin Mus.) ; Ean- 

 giora, New Zealand (South Island), one male, one female (Coll, Dune- 

 din Mus.). 



Genus PARASTACUS Huxley. 



Parastaeus Huxley, Proc. Zool. Soc. London, 1878, p. 771. 



Type, Asfaeus pilhnanus von Martens. 



Form cambaroid. Rostrum of moderate width, rather flat above, 

 marginate, entire or armed with a pair of denticles near the tip. 

 Antennal scale broad. Anterior process of epistome broadly triangu- 

 lar. Superior margin of hand not carinate. Carajjace and abdomen 

 smooth (without prominent spines or tubercles). Telson and posterior 

 pair of abdominal appendages more or less membranaceous at distal 

 end, but no sharp line of demarcation between the membranaceous 

 and calcified portions. Median carina of inner branch of the posterior 

 abdominal appendages terminating not far from the posterior border 

 (usually in a small spine) ; transverse suture of outer branch one-third 

 way from the posterior border. Gills forty, arranged as shown in the 

 subjoined table : 



Abthrobeanchi^. 



Somite. Pouobranchi.^5. . . Pleurobranchi^. 



Auteiior. Posterior. 



VII. . . . O(ep)-orep) . . . . . . . . = 0(epr(.rep) 



VIII. ...1....1....0....0 =2 



IX. ... 1 .... 1 .... 1 .... =3 



X. ...1....1....1....0 =3 



XI. ... 1 .... 1 .... 1 .... 1 =4 



XII. ...1....1....1....1 =4 



XIII. ... 1 .... 1 .... r .... 1 = 3+r 



XIV. ...0....0....0....1 =1 



6-t-ep rorep-f-C + 4+r -|- 4 ^= 20+*-+ep/-orep 



Hahitat. — South America (and Mexico?). 



Von Martens^ notes the existence of a pair of genital orifices on the 

 basal segment of the third pair of legs in a male Parastaeus pilimanus 

 and in a male P. hrasiliensis. The coexistence of sexual orifices in 

 both the third and fifth pairs of legs of the same individual appears to 

 be the normal condition in the burrowing species of Parastaeus. I 

 have found it in every specimen of the followiTig S])ecies examined: 

 P. safforfli, P. varicosus, P. defossus, and P. liassleri. In most cases 

 the vulvaj are closed by a chitinous membrane. 



PARASTACUS SAFFORDI, new species. 

 (Plate LX VIII.) 

 Rostrum of moderate length, i)lane above, with raised toothless mar- 

 gins, which extend backward for a short distance on the gastric area 

 inside the jjostorbital ridges; margins parallel throughout their basal 

 third, then gradually converging to the acute, depressed acumen; the 

 end of the rostrum reaches to the distal end of the antennular pedun- 

 cle; infero-lateral margins fringed with long cilia. Cephalo-thoiax 

 laterally compressed. Postorbital ridges continuous, parallel with each 



1 Sitzungs-Berichte der Gesellschaft naturforschender Freunde zu Berlin, 1870, p. 3, 



