28 ANNALS OF SCOTTISH NATURAL HISTORY 



found to be constant. The same form turns up time and again, 

 identical in size and shape of spines. Till something more is known 

 about the development of these animals, from the egg to the adult, 

 I think it would be rather unsafe to follow the precedent set by 

 Richters when he described M. echinogenitus from peculiarities of 

 the egg only. 



M. hufdandi, Richters (not Plate, C. Sen.?) (Fig. 18). If it lx- the 

 case, as stated by Richters, that M. hufelandi and M. echinogenitus 

 are indistinguishable except by their eggs, then the egg which 

 he figures is not M. Iwfelandi, since Plate earlier figured 

 another form, with blunt conical processes, as that of the 

 species (3). 



Macrolriotus sp. (Figs. 6 and 7). Differs from J/. /ii/fe/andi, Richters, 

 in the shorter thicker processes, with bulging outline. 



M. /u/fe/a/idi, Plate (Figs. 8 and 9). -Although this is not identical 

 with the egg figured by Plate, the form of the spines is the 

 same. 



Macrobiotits sp. (Figs. 10 and 11). Processes hemispherical, set 

 very close together. Similar to an egg figured by Richters 

 (6, Plate V., Fig. 4) as a variety of M. echinogenitus^ but the 

 processes are lower. 



Macrobiotus sp. (Fig. 12). Similar to an egg figured by me (1, 

 Plate IV., Fig. 20), but the processes relatively shorter and 

 broader. 



M. cchino^nHiis, Richters (Figs. 13, 14, and 15). Fig. 13 is nearly 

 typical ; Fig. 14 is the form which appears to be commonest 

 in Scotland, the points longer and curved ; Fig. 15 appears to 

 be a modification of the egg of this species, a hemispherical 

 basal portion bears a sharp, straight spike. 



J/. toivnifer, Richters (Figs. 16 and 17). The most interesting of 

 the eggs found on Ben Lawers. It differs from all other spiny 

 Macrobiotus eggs in that it is oval, while they are spherical. 

 Richters (5 and 6) says that the eggs are covered with small 

 weak spines. The Ben Lawers egg agrees in this respect, but 

 the form of the spines differs from those figured by Richters (6). 

 They are shown as small, straight spikes, evenly tapering and 

 without expanded basal portion. Ours have a minute hemi- 

 spherical base, on which rises a very slender undulate seta. 

 The egg contained a living young, with well-developed teeth, 

 but the pharynx was not clearly seen. With the exception oi 

 this egg, none of Richter's species which possess the circlet oi 

 spines at the base of each claw, have yet been seen in this 

 country. 



