Clare Island Survey — Arctiscoida. 37 9 



Macrobiotus sp. ? (Plate II., figs. 9a- 9b.) 



Egg like that of M. harmsworthi, with closely set acuminate processes 

 (fig. 9b). Pharynx of young in the egg with two short rods — first twice as 

 long as broad, second quadrate — and no comma ; teeth thick ; gullet of 

 moderate width ; claws not seen. 



This might be M. echinogenitus Eichters b ; but in that species the pharynx, 

 when so well developed as in the figure, would usually show the comma 

 distinctly. 



Macrobiotus hibernicus sp. n. (Plate III., figs. 15a-15c.) 



Specific characters. — Size moderate. Claws of Diphascon-type. Gullet 

 slender ; pharynx with three short rods. Eggs round or oval, thick-shelled, 

 studded with nail-like rods embedded in a hyaline matrix, the rods arranged 

 in a reticulate pattern. 



Egg about 60 fj, by 70 /x. The rods have somewhat bulbose bases, are 

 contracted in the middle, and expanded at the end into a broad head 

 like that of a nail. The size of the head varies. The reticulate pattern on 

 the surface is fairly regular, the spaces enclosed nearly circular and about 

 15 /tiin diameter. 



The young squeezed out of the egg was 140 ll in length. The gullet is 

 slightly expanded at the end in the pharynx:. The rods are nearly equal, 

 about twice as long as broad, and there is a comma. The claws were too 

 small to allow details to be accurately seen. The Diphascon character does 

 not appear to be very pronounced, the pairs being nearly equal, with the long 

 claw of one pair somewhat produced. This shows an approach to the type of 

 hufelandii; but it is not safe to take the characters of the claws from 

 the young in the egg, as their development may be incomplete. The teeth 

 and pharynx are fully developed earlier than the claws. Eyes were not 

 seen. 



The size of the adult cannot be given, as, although they may have been 

 present in the material, the identity of any adult with the egg could not be 

 proven. 



Closely related to M. arcticus and M. hastatus. Although the observations 

 are incomplete and the adult is unknown, the reticulate pattern on the egg 

 and the three rods in the pharynx sufficiently distinguish M. hibernicus from 

 these species. Both of them have only two rods in the pharynx, and 

 the rods on the egg are more numerous and closer together, not forming a 

 reticulation. 



Judging by what is known of the related species, it may be expected that 

 B.I. A. PROC, vol. xxxi. B 37 



