ON ARCTIC TARDIGRADA. 677 



In Prince Charles Foreland adults reached to 800m long. 



M. crenulatus, Richters (12). (Plate I. figs. 6a to 6c.) — Discovered by Richters 

 in Spitsbergen, this species was observed in Prince Charles Foreland and Franz Josef 

 Land. In our examples the last leg was sometimes papillose, as in Richters' M. 

 granulatus, and there was a papillose process on the front of each leg, not referred 

 to by Richters. The crescent in front of the claws is merely wrinkled, not spiny, and 

 the rods in the pharynx are not nearly so thick and strong as in examples of 

 M. granulatus which Prof. Richters has kindly sent me. 



The colour was dark brown. The largest examples measured 750m long, the 

 pharynx 66m long. 



M. harmsworthi, sp. n. (Plate I. figs. 7a to 7d) : — 



Specific Characters. — Size moderate, blood pale yellow. Teeth nearly straight,, 

 with bearers ; pharynx somewhat long, oval ; thickenings, four in each row ; first, short, 

 attached to the gullet, second, third, and fourth narrow rods, the fourth a little longer 

 than the others. Claws of hufelandi type, united half way, one claw of each pair much 

 longer, with two large supplementary points. A crescent-shaped ridge in front of each 

 pair of claws, crenate on the last legs, plain on the others. Eyes very small. 



Length up to 500m, pharynx 52m, claws 24m. 



Related to M. crenulatus, Richters, it is distinguished by the pharynx with 

 three narrow rods, and the crescent crenate instead of closely wrinkled. 



Cape Mary Harmsworth, Franz Josef Land, Spitsbergen. Also in Shetland. 



M. arcticus, sp. n. (Plate I. figs. 5a to 5f) : — 



Specific Characters. — Spiny eggs with rod-like blunt processes embedded in hyaline 

 matrix. Egg small, oval or round ; spines subclavate, slightly expanded, and blunt 

 at tips. Pharynx short, oval ; thickenings three in each row ; first, nut, attached to^ 

 gullet ; second and third short rods, almost as broad as long ; teeth curved, with 

 bearers. Claws V-shaped, one of each pair longer, the long claw of one pair very long. 

 Dark eyes. 



The adult is unknown, but the young of Macrobiotics rarely differ in any important 

 respect from the adult. Diameter of egg, over the spines, 83m, pharynx in egg 20m. 



The only close relative is M. hastatus, Murray, which has egg spines similarly 

 embedded in a hyaline matrix. The egg of that species is larger, the spines larger and 

 more complex, the rods in the pharynx longer. 



Prince Charles Foreland and Franz Josef Land (fig. 5/). 



The egg from Franz Josef Land is smaller, oval, 65m in long diameter. A similar 

 egg to the smaller one, but with thicker spines, has been found in South Africa. 



Another egg of the same type, but with shorter, round rods, occurred in Loch 

 Ness, and is figured in "Scottish Tardigrada" (8), Plate IV. figs. 27a to 27 d. The 

 animal hatched from this last egg was very similar to M. arcticus. 



M. pullari, Murray (8). — An egg found in Prince Charles Foreland resembles that 

 of this species and M. dispar. In size it comes nearest to M. pullari. 



TRANS. ROY. SOC. EDIN., VOL. XLV. PART III. (NO. 25). 96 



