Zoology.'] NATURAL HISTORY OF VICTORIA. [Crustacea. 



Plate 15. 



ASTACOIDES SEEKATUS (Shaw sp.). 



The Murray Lobster. 



[Genus ASTACOIDES (Guer). (Sub-kingd. Articulata. Class Crustacea. Order 

 Macrura. Fain. Astacidse.) 



Gen. Char. — General form and characters of Astacus, but with the first segment of the 

 abdomen destitute of appendices. Abdominal feet membranous, with a row of small calcareous 

 plates on each margin. Outer pair of tail fins jointed, with the distal portion thinner and less 

 calcareous than the proximal one. Inner lobes not distinctly jointed, and calcareous to the end. 

 Rivers of Madagascar and Australia.] 



Description. — Beak elongate, acutely pointed at the apex, hollow above, with 

 three or four strong teeth on the lateral bounding ridge of each side, usually a little 

 loDger than the base of the outer antennae. Carapace with several large scattered 

 spines on the sides in front of the nuchal furrow, which is very deeply impressed. One 

 or sometimes two rows of large conical spines border the posterior side of the nuchal 

 furrow, and extend along the division between the lateral vertical portion of the 

 carapace and the horizontal dorsal portion. Whole of the vertical sides behind the 

 nuchal furrow, or branchial regions, covered with small round prominent irregular 

 tubercles about their own diameter apart ; hepatic region or sides of the carapace in 

 front of nuchal furrow set with numerous scattered conical spines, the upper ones 

 larger. Segments of the abdomen having a row of very large conical spines on each 

 side of the middle, the points usually directed slightly forwards j outside of this a second 

 row of still larger ones, and, nearer the outer end, a third row, slightly more slender, 

 not occurring on the first segment or thft last, but two of which are usually found on 

 the dilated margin of the second segment. The middle segment of the tail fin is 

 sometimes smooth, but sometimes has 3 or 4 small conical spines and a variable 

 number of smaller and more numerous pointed tubercles. Anterior feet or claws 

 nearly equal : the outer edge of the hand has a row of 13 or 14 large compressed 

 spines, with a second row a little beneath in the middle portion ; the inner edge 

 of the hand has usually 5 smaller spines, and there is a blunt conical one on the 

 upper aspect, about a third of the width from the inner edge, at junction with 

 carpus ■ outer edge of last joint or movable finger smooth, rounded. Carpus with 

 3 sharp conical spines on the outer edge and 3 much stronger on the inner edge, 

 of which the anterior one is much the largest, and the anterior edg^e has 2 strong 

 conical spines on the lower aspect. The next joint of the leg has 2 rows of large 

 conical spines on the lower edge, and from 4 to 8 irregularly disposed on the upper 

 edge. Four hinder pairs of legs with very irregular small spines. Anterior median 

 triangular process of epistome about as long as wide. The outer antennae are inserted 

 below the inner ones. Color : the anterior legs, the middle of the back, and the apices 

 of the spines and tubercles rich creamy white or ivory color; the ground color of the 

 other legs, sides of carapace, and the abdomen pale prussian blue of varying* intensity 

 in different individuals, or sometimes mottled with dull olive-green. The semi- 

 corneous flexible edges of tail fin brownish. Length of large specimen from snout 

 to tip of tail, 12 inches 6 lines ; diameter of carapace, 3 inches ; length of carpus, 

 1 inch 7 lines ; length of hand, 4 inches 3 lines ; width of hand, 2 inches 3 lines. 



Reference. — Cancer serratus, Shaw. Zool. N. Hoi. t. 8. — Potamobius id. 

 White, P. Zool. S. 1850, p. 95. — Astacoides spinifer, Heller, Reise der Novara 

 Crustaceen. Zoologisher Theil. Band. 11. Abtheil. 3, p. 102, t. 9. — Astacus 

 armatus Von Martens, Ann. and Mag. Nat. Hist. 1860, p. 359. 



Dec. ii. [ 17 ] c 



