648 



MR JAMES MURRAY ON 



General Distribution — continued. 





Britain. 



Polar Regions. 



Other Regions. 



31. M. ambiguus, Murray . 



Shetland. 



Arctic. 



Europe (Geneva). 



32. M. pullari, Murray 



Scotland. 





... 



33. M. hastatus, Murray 



Scotland. 





Europe(Switzerland). 



34. M. dubius, Murray 



Scotland, Shetland. 







35. Diphascon chilenense, Plate . 



Scotland. 



Arctic, Antarctic. 



Europe, Asia, 

 America. 



36. D. bullatum, Murray . 



Scotland. 







37. D. oculatum, Murray . 



Scotland. 







38. D. alpinum, Murray 



Scotland. 



Antarctic. 





39. D. spitzbergense, Richters 



Scotland. 



Arctic. 





40. D. angustatum, Murray 



Scotland. 



Arctic. 



Europe (Germany). 



41. D. scoticum, Murray 



Scotland. 



Arctic. 





Notes on the Genera and Species, with Descriptions of New Species. 



Genus Echiniscds. 



Structure. — In this genus the structures which serve for specific distinction are 

 the number of plates, their arrangement, texture, setse, spines, or other processes ; the 

 fringe on the last legs ; the barbs on the inner or outer claws. Two characters, the 

 eggs and the pharynx, of the greatest value in the genus Macrobiotus, are of little 

 service here, being invariable. 



Eggs. — In all known species they are smooth, round or oval, and they are always 

 laid in the skin at the moult. 



Pharynx. — In the majority of known species there are none of the rods so char- 

 acteristic for each species of Macrobiotus. Professor Richters has found such rods 

 in E. islandicus, and I have seen them in a species not yet identified. 



Legs. — The spine on the first leg, which is given as a specific character of E. creplini 

 and some other species, is not distinctive. It is present in most species. Its size may 

 be characteristic, as in E. reticulatus, in which it is of exceptional length. An un- 

 described species has similar spines on all the legs. The fringe on the fourth legs, 

 found in the great majority of species, changes with age, but is believed to be of 

 characteristic form when fully grown. The barbs of the inner claws, also present in 

 most species, appear to be invariable. They are often larger in the larva. E. arctomys 

 and E. borealis (Murray 12) are without them. Straight spines near the base of 

 the outer claws are known only in a few species (E. blumi, E. merokensis, E. oihonnse, 

 and E. granulatus ?). They are not invariably present in the same species. They appear 

 to be absent in the young and to develop with age, and in one species they increase in 

 number with age till there are three on each outer claw of the last leg (E. granulatus). 



Plates. — Professor Richters distinguishes six segments (see Plate I. fig. 4a, I to 

 VI), of which I, II, III, IV, and V correspond to the brain and the four ventral ganglia. 



