INTERNAL ANATOMY OF THE GAMASIN^. 317 



Dorsal surface with four longitudinal rows of about ten spines on the dorsum, and two 

 rows, or a double row, all round the periphery except just the anterior edge, on which 

 there are two fine spines, near together, projecting forward. The dorsal spines are 

 sparsely set, increase greatly in size from the anterior to the posterior end of the 

 body, and do not overlap, except at the rear. The anterior spines are sharply pointed ; 

 those of the female about -03 millim. long : the hind spines are very thick, blunt, and 

 spatulate ; those of the female about - 12 millim. long. 



Ventral surface. Female with anal plate fused with ventral, very large, covering half 

 the abdomen, and divided by fine lines into scale-like spaces. Genital plate almost touching 

 the fused ventral and anal. It is bell-shaped, i. e. rounded anteriorly, straight posteriorly ; 

 a central triangle with the point forward is the most chitinized part in this plate ; the 

 peripheral band is also chitinized, but two lenticular spaces between are slightly chitinized 

 and look almost like foramina. Sternal plate normal ; there are two small plates near 

 its anterior edge and two near its posterior corners. Stigmal plate almost straight, but 

 clavate posteriorly. The male, in addition to the usual sexual differences of the plates, 

 has in the middle of the ventro-anal plate, and about midway between the anus and the 

 coxae of the fourth leg, a large and singular projection standing straight downward and 

 formed like a short length of concave gutter (half tube), from the lower edge of which 

 project two large chitinous apophyses, much more strongly chitinized than any other part 

 of the body. There are three or four spines round it. I do not know the function of this 

 organ. It has the appearance of a male genital armature, but the ordinary male genital 

 aperture is quite plain and unmistakable in its usual place at the other end of the body, 

 viz. just in front of the anterior edge of the sternal plate. 



Habitat. I found a very small number of specimens near Innsbruck, in Tyrol, on the 

 stumps of dead pine-trees, and while this paper has been passing through the press I 

 have found the species in large numbers in England on the underside of fungi growing 

 on old tree-stumps at Goring in Oxfordshire. 



I regret that want of space on the Plates has prevented my figuring the ventral surface 

 of this creature. 



EXPLANATION OF THE PLATES. 



A. Anus. br. Brain (so-called). The small dark cells are 



(if. Acetabula for insertion of the coxae of the the cortical or corpuscular layer, the rest 



legs. The figures 1, 2, 3, 4 refer to the the inner or fibrous mass. 



1st, .2nd, 3rd, or 4th pair of legs. 

 ap. Anal plate. 

 dp. Bipilate appendage (Winkler's labium, 



Kramer's " Bauchtaster"). 



cm. Front caecum of the ventriculus. 



cm 1 . Upper hind caecum of the ventriculus. 



cm 2 . Lower hind caecum of the ventriculus. 



