Descriptions of some Australian Phyllopoda. 



of which the eyes occur. Posteriorly the carapace exhibits a 

 low dorsal keel, extending for about 1/3 of its length and be- 

 coming more elevated behind. This keel terminates in a tooth- 

 like projection dividing the posterior emarginatiou into two 

 halves. 



When the animal is viewed from the ventral face (fig. 2) 

 the frontal part of the carapace is seen to form below a semi- 

 lunar, shelf-like duplicature, to the middle of which the labrum 

 is articulated. The anterior extremity of the carapace thereby 

 acquires a shovel-like appearance. 



As to consistency, the carapace is very thin and flexible, 

 with the surface quite smooth and shining, allowing the under- 

 lying parts to be faintly traced. Within its 2 lamellæ are 

 imbedded the 2 shell-glands, which are easily observable exter- 

 nally as a rather broad band extending on each side of the 

 carapace from the cervical sulcus (see fig. 1). The lateral 

 edges of the carapace are generally quite smooth and somewhat 

 thickened; but in some specimens there are found in their 

 most posterior part a few irregular serrations. The edges of 

 the posterior emarginatiou are in all the specimens fringed 

 with well-marked, though rather small, acute denticles. 



The body is connected with the carapace only quite in 

 front, its far greater part, extending behind the mandibular 

 segment, being only loosely covered by it and freely mobile. 

 This free part of the body gradually tapers distally, and is 

 divided into 28 rather uniform segments, of which the 11 an- 

 terior ones may more properly be referred to the mesosome, the 

 12 succeeding ones to the metasome, and the last 5, non-pedi- 

 gerous segments to the urosome or tail. There are, however' 

 no distinctly marked limits between these 3 divisions, and it 

 is only by the relation of the appendages, that they admit of 

 being defined. Generally about 10 segments may be found 

 uncovered, but in some cases, only the caudal segments are 

 exposed behind the carapace. The latter are perfectly cylindric 



