PEOF. W. A. HAS WELL ON AUSTRALASIAN POLTCLADS. 471 



and ejaculatoiy duets, would suffice to distinguish Diplosolenia from all other 

 Tlunoceridce. 



Idioidcma, Woodworth (26), resembles Diplosolenia in the exceptional feature of the 

 complete separation of prostatic and ejaculatory ducts ; but it has marginal eyes, has, 

 apparently, no penial stylet, and has a median vesicula. 



Planocera has the ejaculatory and prostatic ducts uniting to form a common duct ; its 

 penis is lined with chitinous spines, and the vagina gives rise to a bursa copulatrix : the 

 receptaculum seminis is unpaired. 



StT/lochoplana, again, has the prostate intercalated in the course of the ejaculatory 

 duct, has a median vesicula, a single receptaculum, and possesses a bursa copulatrix ; 

 while Styloclms has marginal eyes, the reproductive apertures situated close to the 

 posterior end, has the prostate separate, but with its duct u.niting with the ejaculatory 

 duct, a single vesicula, and no receptaculum. 



ParapJanocera, though it has paired vesiculpe, resembles Planocera in the character 

 of the penis and in the unpaired receptaculum ; it also has a muscular diverticulum of 

 the vagina of the nature of a bursa copulatrix. 



Leptoplana austealis, Laidlaw. (Plate 36. figs. 3-5.) 



This is, so far as my data go, the most widely distributed, as well as one of the largest, 

 of the Australasian Polyclads. It is one of the commonest of the Port Jackson species, 

 and was obtained also at Jervis Bay, on the southern part of the New South Wales coast. 

 It is l^y far the commonest species on the coast of Tasmania, and it extends also to 

 New Zealand. 



Leptoplana austraUs may be identical witli Bloncus hadlus of Stimpsoa (23), or with 

 D. oblongas of the same author, both of which were found in Port Jackson, and it may 

 also be tlie same as Polj/cells australis of Schmarda (20), which was found on the New 

 South Wales coast. But the characters given by the authors named are not of a nature 

 to justify even generic determination. Thus Stimpson's detinitiou of the genus JDlouc/f-s 

 runs : — " Corpus planum, dilatatum. Caput corporc continuum. Os subcentrale. 

 Ocelli numerosi, in umboues duos claros subdistantes dispositi. Maricolse." Tiie 

 description which he gives of D. badiits is as follows: — " Body half as broad as long, of 

 a reddish-brown colour above, with a flake-white dust intermixed. Anteriorly there are 

 two prominent circular knobs, which contain, scattered over the entire surface, the very 

 numerous and minute eyes. Below the body is of a pale sepia colour, except the white 

 digestive organs, and the mouth is placed behind the centre. Lengtix 1'5 ; breadth 

 0'75 inch." I>. oblongus is stated to differ from D. hadius mainly in having a clear space 

 around the eyes on each knob. 



Schmarda's Pohjcclls australis may be this species, but the characters gi^^en and the 

 figure would not warrant an identification. The following is the description: — 



" Der Korper ist platt, liinglich, vorn abgerundct und riickwiirts kaura. weniger 

 verschmachtigt. Die Parbe des Riickens ist dunkelbraua mit unterbrochener blasser 

 Mittelliuie. Die Bauchseite ist rothlichbraun. Liinge 30 mm., Breite 13 mm. Die 

 Augen stelien in zwei Gruppen am endc des crsten Sechstels, sie siad cinander selir 



