240 FISHES OF AUSTRALIA. 



the Short-headed Lamprey (Mordacia mordax} and the 

 Wide-mouthed Lamprey (Geotria australis'). Little is 

 known of their habits. 



THE LANCELETS. 



(Group: CEPHALOCHORDATA.) 



THE Lancelets, usually known under the name of "Amphi- 

 oxus," form a small group of little fish-like forms, in 

 which there is no skull and no vertebral column. They are 

 not true fishes, though as they are usually grouped with 

 them, they are deserving of mention here. They are 

 slender, transparent or semi-transparent animals of 2 or 3 

 inches in length, pointed at both ends, frequenting shallow 

 coastal waters and burrowing into the sand with great 

 rapidity. 



Three species of Lancelet are found on the coast of 

 Australia ; these being Branchiostoma bassanum, B. belcheri 

 and B. cultellum. The first is a native of New South 

 Wales and Victorian waters, while the others have been 

 taken from the coast of Queensland. 



The Lancelets are all included in one family; that 

 known as the Branchiostotnatidcs. 



