NEW TYPE OF MALACOSTRACOUS CRUSTACEAN. 3 



Koonunga cursor, Sayce. 

 Specific Description. 



Anterior portion of the body of subcylindrical form, becoming gradually rather broader, 

 deeper, and cylindrical posteriorly. All the segments of the thorax and abdomen subequal. 

 Abdomen equal in length to the thorax, last segment not longer than the preceding one, 

 with one or two dorsal spines close to the attachment of the telson. Telson entire, slightly 

 broader than its length, of triangular form and rounded apex, margin fringed with two 

 or more series of stout spines. Uropod with peduncle extending to half the length of 

 the telson, its branches somewhat longer than the peduncle, inner one fringed along the 

 inner margin with upturned spines, and three longer ones at the apex pointing outwards ; 

 outer margin and apex fringed with very long feathered seta? ; outer branch fringed 

 with long feathered setae, and the outer margin also with a row of upturned spines. 



Mandibles each with a broad cutting-plate, that of the left side curvino- outwards, 

 and the edge divided into six stout teeth ; that of the right side also broad, curved in 

 the reverse direction, and the edge divided into five stout teeth ; molar process similar 

 in each, forming a well-extended broad ridge clothed with short, stout setae, surrounding 

 a minute triturating surface with chitinoid papillae. 



Maxillipeds rather stouter than the legs, extending directly forwards about as far as 

 the distal end of the peduncle of the upper anteunae, the seventh joint (dactylusj minute, 

 stout, and bearing four claws on the rounded extremity. The seventh joint, also, of 

 each of the other limbs minute, and bearing three long, stout claws, the middle one 

 rather longer than the other two, which are placed closely on each side of it and 

 quite similar to each other. 



Colour. — General appearance marbled dark brown. Microscopically showing a yellowish 

 stratum, thickly dotted over with rounded areas composed of black granules. 



Length. — Largest specimen measured 9'5 mm. 



Occurrence. — From freshwater reedy pools beside a tiny runnel joining the Mullum 

 Mullum Creek, Bingw T ood, near Melbourne. 



Remarks. — It is remarkably active ; usual form of locomotion running, but can spring 

 forcibly forwards and also swim easily. It shuns strong light. 



Detailed Description. 



The largest specimen I have seen measured 95 mm. in length, and it differed 

 morphologically in no important degree from others of at least 7 mm. The following 

 description is made after examination of several specimens between these two sizes, some 

 of which were seen alive. Its nearest ally appears to be Anaspides tasmanice, G. M. 

 Thomson, and I have made comparisons with it from descriptions and drawings by 

 Thomson (Trans. Linn. Soc, Zool. (2) vi. 3) and Dr. W. T. Caiman (Trans. Roy. Soc. 

 Edinburgh, xxxviii. pt. iv.). 



In general appearance the colour is irregularly marbled dark brown on body and 

 appendages ; microscopically the dark areas are resolved into small irregular and roundish 

 patches, composed of dark brown and black granules, the intermediate stratum being 

 yellowish. Alcohol specimens show scarcely any difference in colour. 



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