1 1 (S THR VICTORIAN NATURALIST. [Vol. XXIV. 



Should tlic opinion preponderate that the Schizopoda, with the 

 luiphausid and Mysid types both induded, be kept for the present 

 as a natural group, then Anas])idacea may be included as a tribe 

 of that group. 



I am aware in joining the present species to Anaspidacea that 

 it originates an order possessing botii stalked and sessile-eyed 

 forms, but I feel confident that the close relationship shown in 

 other respects of this new species to Anaspidcs warrants such a 

 union. 



Fundamentally the present species has the well-known Schizo- 

 pod characters, and, of the two rather widely divergent types of 

 that order, it has marked affinities with the Euphausid, and to a 

 lesser degree with the Mysid type, as well as having a strong like- 

 ness to the primitive forms of Ipsoda and Amphipoda. 



Considering the stalked eye as a primitive character, and 

 dominant throughout the main stem of descent of the crustaceans, 

 and the sessile-eyed forms as a lateral divergence, it appears to me 

 that the present form is an early stage of such divergence. 



It will not be disputed that the present species in general form 

 and structure is like Anaspides tasjuanice, G. M. Thomson, a note- 

 worthy species in fresh-water pools on the summit of Mt. 

 Wellington, Tasmania, and in Lake Field, situated 40 miles from 

 the above situation, at an elevation of about 4,000 feet. 



Anaspides differs from other Schizopods in possessing no 

 vestige of a carapace, and has eight distinct thoracic somites. 

 The present species has marked affinities with it, but differs in a 

 good many minor characters and fundamentally in tlie eyes being 

 sessile, there being no antennal scale, and in the coalescence of 

 the first thoracic somite with the head. 



The loss of stalked eyes, carapace, and scale-like exopodite 

 on the antenna — each, I think, acknowledged as primitive features 

 — while in most other respects quite of a Schizopod type, marks the 

 present species as the most primitive sessile-eyed Malacostraca 

 at present known, and it is no doubt a very ancient type. I may 

 also note that Caiman has shown that Anaspides closely resembles 

 some of the oldest fossil Malacostraca (Uronectes, &c.) 



Specimens were collected from small fresh-water reedy pools 

 beside a tiny little runnel which joins the Mullum Mullum 

 Creek, Ringwood, near Melbourne, during an excursion of the 

 Nature Study Class for teachers, under the direction of Mr. J. A. 

 Leach, M.Sc, to whom I am indebted for specimens. 



Order.— ANASPIDACEA, Caiman, 1904. 



This order, so far, has not been defined. 



Body generally slender, of nearly cylindrical form, integument 

 thin. Carapace absent. Thoracic somites distinct, or with the 

 anterior one fused with the head. Abdomen of about equal 

 length to the cei)halon and thorax combined, somites distinct, 



