668 rnocEEDixas of the national museum. vol.** 



Subfamily PARASTACIXJE. 



First abdominal somite devoid of appendages in both sexes; podo- 

 branchiae lacking a bilobed plaited lamina, although tlie stem may be 

 expanded into a wing; epipod of first maxilliped generally furnished 

 with branchial filaments, coxopoditic seta* hooked at the end; telson 

 not divided by a transverse suture. 



ASTACOIDES Guerin. 

 Astacoides Gukrin, Ecvue Zoologique, II, p. 109, 1839. 

 Type, Astacoides goudotii Gn6iiTx=A stacus madagascariensis Audouin et Milne-Edwards. 



Eostrum short, quadrilateral, concave above, margins furnished with 

 small teeth or tubercles. Antennal scale very small. 1 Anterior process 

 of epistome long triangular. Superior border of the hand dentate. 

 Sides of the carapace armed with small tubercles, some of which assume 

 the form of small spiues. Number of well-developed gills reduced to 

 twelve on each side of the body; posterior arthrobranchire rudimentary 

 and functiouless ; one pair of pleurobranchise (on the fourteenth somite) ; 

 the branchial formula, according to Huxley, 3 being as follows: 



Arthrobranchi^s. 



Somite. Podobranchi^e. . . Pleurobranchi^e. 



Anterior. Posterior. 



VII. . . . 0(epr) .. .... .... = 0(epr) 



VIII. ... 1 . -... r .... .... = 1 + r 



IX. ... 1 .... 1 .... =2 



X. ... 1 .... 1 .... r .... = 2 + r 



XL ... 1 .... 1 .... 7 1 ... . = 2 + r 



XII. ... 1 .... 1 .... r .... = 2 + r 



XIII. ... 1 .... 1 .... r .... = 2 + r 



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



6 + epr + 5 + ;- + 4r + 1 = 12+5r+epr 



One species known. 

 Habitat. — Madagascar. 



ASTACOIDES MADAGASCARIENSIS (Audouin et Milne-Edwards). 



Astacus madagascariensis Audouin f.t Milne-Edwards, Journ. del'Institut, 1839, 



p. 152; Arch, da Mus. d'Hist. Nat., II, p. 35, pi. in, 1841. 

 Astacoides goudotii Guerin, Eevue Zoologique, II, p. 109, 1839. ^ 

 Astacus (Astacoides) madagascariensis Erichson ,Arch. f. Naturgesch., 12ter Jalirg., 

 i, p. 89, 1846. 



' Erroneously said to be wanting by Guerin. 



2 Proc. Zool. Soc. London, 1878, p. 775. 



3 Guerin's description of the Madagascar crayfish must have been published about 

 the same time as Audouin and Milne-Edwards's. The Eevue Zoologique was issued 

 monthly. Gu6rin's description occurs in the April number, 1839. Audouin and 

 Milne-Edwards's description in the Institute, p. 152, was communicated to the 

 i-'ociete Philomatique on the 27th of April, 1839. In cases like this it seems reason- 

 able to retain the name adopted by the next following author who treated of the 

 species — in this instance, Audouin and Milne-Edwards ; n the Archives du Museum 

 d' Histoire Xatnrelle, II, 1841. 



