664 MR JAMES MURRAY ON 



happened so constantly that I suppose such shelter is deliberately sought for the eggs, 

 though the selection of the shells of Alonella nana is probably only due to their great 

 abundance. 



Bog pool at Fort- Augustus, 1904. Loch Tay. Also collected in Switzerland by Dr 

 Chas. Linder. 



M. dubius, sp. n. (Plate III. figs. 17a to 17c.) 



Specific characters. — Size moderate. Pharynx elliptical, somewhat narrow, of the 

 hufelandi type ; long rod apparently formed by the junction of two rods, of which the 

 second is much shorter. Claws of echinogenitus type, one of each pair longer. 

 Hyaline. 



Size 312/*, no eyes. Egg unknown. Saxavord Hill, Unst, Shetland, September 

 1906 ; bog pool at Fort- Augustus, November 1906. 



Macrobiotics, sp. ? (Plate II. figs. 12a, 126.) 



The egg erroneously recorded as that of M. coronifer (8) has not yet been identified, 

 but is undoubtedly distinct from any species yet named. It agrees with M. coronifer 

 in the oval form and small weak spines, but has, as JRichters points out, nothing else 

 in common with it. 



Diphascon. 



The genus Diphascon now rests upon a very slight foundation. The elongated 

 flexible gullet, on which the genus was founded by Plate, is a character shared by 

 various species of Macrobiotus. In Macrobiotus this character is abnormal or excep- 

 tional ; in Diphascon it is believed to be normal and permanent. I thought to dis- 

 tinguish a peculiar Diphascon type of claw (9), and it is true that all the species known 

 have claws of one type, but it is the type found in Macrobiotus oberhauseri. 



The genus can therefore only be defined as having claws of the oberhauseri type, 

 and normally possessing a more or less elongated and flexible gullet. So far as known, 

 the eggs are smooth and are laid in the skin. Eyes are present in one species only. 

 In many species the pharynx is narrow and elongate, which is never the case with 

 Macrobiotus, which has the pharynx in all known species shortly oval or roundish. 

 The elongate pharynx cannot be made a generic character, as one or two species have 

 it nearly round. Simplex forms occur. 



Professor Richters also expresses little faith in this genus, one species of which, 

 D. spitzbergense, he has described. Admitting the slight stability of the genus, and 

 turning to the consideration of the described species, those appear to be all sufficiently 

 distinct forms, even if we admit that the elongate gullet may be an abnormal 

 development. 



One feature alone sufficiently distinguishes the species of Diphascon from the great 



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