116 Proceedings of the Royal Irish Academy. 



minutely spiculate. Crista fig. 31) long and slender , the anterior extremity 

 is distinctly pointed, and there is only one bristle in front of the long sensory 

 hairs. Eyes small, and set close to the side margins of the cephalothorax. 

 I/Cgs slendei', rather feebly developed, the fii-st pair much longer than the 

 othei-s. 



Fanuly TEOMBIDIIDAE. 

 Microtrombidium pusillum (Herm.) var. major nov. (I'l. XXIII, fig. 32 a,c.) 



lycngth, 1400^ to 1700/* ; breadth, about 900/i. Colour red ; shape ovate ; 

 in the ovigerous female it is more elongate ; shoulders not prominent. 

 Epidermis reticulate and densely covered with plumose spines (tig. •32a) ; these 

 are slightly bent, constricted at the base, and have bristle-like extremities ; 

 their length varies from -ibn to oO/i. Cephiilothora.\ very small ; the crista 

 (fig. 32 b) is strong; anterior extremity ^vnth a striated expansion at each 

 side; sensory area rather small, with a thick chitinous border, surrounded by 

 a ring of pulmose spines A chitinous prwess of the median rod projects 

 into the proximal sensor}* area. Eyes small, lying close to the crista. 



llie palps are of normal length, first two segments equalling those of first 

 pair of legs in breadtli (55/i) ; last segment with a short appendsige and an 

 inner comb of at least five strong spines (fig. 32 c) ; distal extremity slender. 

 Legs short and stout ; the first pair measure about 760/i in length. The last 

 segment has an almost straight dorsal and a rather convex ventral outline 

 (length, 180;j ; breadth, 85,i). 



This variety appt-ars to differ from the typical form in the larger size, longer 

 bo<ly hairs, the form of the tenninal segment of ihe first pair of legs, and in 

 the pi-esenco of a distinct inner comb of spines on the fourth palp segment. 

 In hi.s synopsis of the type, I'erlese remarks "spinis pectinis in latere 

 segmenti quarti intcmis nuUis," though in his remarks on the species he .sajs 

 there is a comb of very minut'e (pufhiwiimi) spint>s pre.'»ent. 



Habitat. — A few 8(XK:iniens occurred under stones in the Pelvelia zone, 

 just below high-water mark, at Anlfry, Co. Galway,June, 1916. 



