BY G. I. PLAYFAIR. 135 



A good many specimens of this form were found in a sample kindly sent me 

 by the engineer of the Perth (W.A.) Water Supply. It is very like Tr. elegaii- 

 tisaima var. ovata from the Sydney Water Supply, hut with a very short stalk. 

 The loriea is ovate, subglobose with rounded sides, narrowed below into a short 

 stipes. Above there is a square neck with everted rim. Membrane smooth, that 

 of the body stout, especially above, pale brown ; but, in every case, that of the 

 neck was hyaline and very delicate, evidently a later growth. One specimen 

 noted was entirely hyaline, pellucid and thin-walled like a Binobryon. 



Trachelomoxas XAPiFORJiis var. brbvicollis, n.var. (PI. vii., figs. 12 — 14). 



Forma jiaullo magis ovata, collo breviore, ore valde everso. 



Long. 48—53 (corp. 3(i— 38), lat. 24—25; coll. alt. 5— (i, lat. (i— 11; caud. 

 10-1 4(u.. Lismore (322, 333. 347). 



A more perfectly ovate form of the type with shorter neck and accentuated 

 rim. A new record for this species. 



Trachelomoxas cuxeata, n.sp. (PI. vii., tig. 15). 



Lurii^a trapezoidea, angulis lateralibus fere rectis; interne cuneata, lateribus 

 plauis ad caudam convergentibus ; sur.sum subtriangularis, lateribus convexis in 

 collum sensim sensimi|ue adscendentibus, ore everso; membrana hyalina scabra. 



Long. 50, lat. 20; coll. lat. 6; caud. long. 14(u,. Lismore (258). 



Lorica somewhat trapezoid with lateral angles almost square. Greatest 

 breadth about l-3rd from the mouth. Froui the lateral angles downward, cun- 

 eate. with Hat sides converging to the tail. Above subtriangidar, sides convex, 

 gradually rising into the narrow-ed neck with everted rim; membrane irregularly 

 roughened. 



Trachelomoxas cibherosa var. LOXiiicOLi.is, n.var. (PI. vii., tig. Ki). 



Lorica eorpore multo compresso; collo longissimo, lateribus parallelis. 



Long. 54, lat. 20; coll. alt. c. 18, lat. 0; caud. long. c. 24^. Lismore (258). 



An elegant form, with the body of the lorica much compressed antero- 

 posteriorly, and with a vei-y long neck. This form and the previous one are 

 both uncommon; they were plentiful, however, alive in one gathering. 



Var. TUMIDA, n.var. (PI. vii., fig. 17). 



Lorica eorpore prae longitudinem multo majore; lollo vix formato; canda 

 minutissima. 



Long. 53, lat. 39; lat. oris 7; caud. long. 3;li. Lismore. 



A form in which the l)ody of the lorica is very large compared with the 

 total length. Above, it is gradually naiTowed to the mouth without any distinct 

 neck; tail quite minute. That polymorjdiism in these and similar organisms is 

 largely a matter of the relative development of component parts, is well exem- 

 plified in this species. This form, var. ItmgicolUs, and the type (long. 53, 54, 

 50^ respectively) aie all about the same size and the characteristic shapes are 

 merely the result of the proportionate growth of the body, neck and tail of the 

 lorica. 



Trachelomoxas rotundata mihi. (PI. vii.. fig. 18). 



Jr. ffibherosa var. nilmidatu Playf., tiiitea, 1915, p. 35, (var. rotunda, by 

 a slip of the pen. in the explanation of the plates, p. 41). 



Long. 40 (corp. 25); lat. 25; coll. alt. 0, lat. G; caud. l<mg. O^ii. Lismore. 



