80 TWELFTH ANNUAL REPORT. 



ent embryo from below and in an earlier stage. Fig. 2 illustrates 

 the relation of the brain to the eye and the very small optic gang- 

 lion. Fig. 9 of plate G gives details of the feet in another species, 

 and the modifications seen in the male of the same species are suffi- 

 ciently shown in fig. 1 of the same plate, which also well illustrates 

 the various sculpture of the shell displayed by this group. Figures 

 4 and 9 of plate F show curious modifications of the post-abdomeu 

 of the male, and fig. 7 exhibits the structural peculiarity of sexually 

 perfect females which is correlated with it or, perhaps we may say, 

 occasions it. 



SUB-FAMILY 1.— EURYCERCIN^. 



A single species constitutes the sub-family, and it will be necess- 

 ary to point out only those points which are distinctive. 



The Eurycercinas differ from the true Lynceidffi and approach the 

 Lyncodaphnidse in having the digestive tract not coiled, with two 

 Cceca in front and the anus at the end of the post-abdomen. Many 

 eggs are produced at once. The male opening is at the base of the 

 abdomen, as in Sididge. The general habitus is, however, lynceid. 

 The males appear in autumn or when, by the gradual drying up of 

 the water or other causes, the continued existence of the animals is 

 threatened. 



I. Genus Eurycercus, Baird. 

 Characters of the sub-family. 



Eurycercus laniellatiis, 0. F. Mueller. 



(Plate H. Figs. 5-6.) 



Lynceuslamellalus, MUELLER, EDWARDS, KOCH, ZADDACH, LTEVIN, LEYDIG. ZENKER 

 Eurycercus lamellatus, BAIRD, LILL.IEBORG, SCHOEDLER, P. E. MUELLER, KURZ, BIRGE, 

 HERRICK. 



Eurycercus laticaudahis, FISCHER, SCHOEDLER. 



A gigantic lynceid, reaching the dimension of 3 mm. The figure 

 of the male .given will sufficiently illustrate the general form. The 

 abdomen is broad and armed behind with a dense row of saw-teeth. 

 The eye is larger than the rather small pigment fleck, and the in- 

 testine is bent upon itself but not coiled. The last foot is found in 

 few other Lynceidee. Acroperus has the same, and Pleuroxus uui- 

 dens also has a rudimentary sixth foot. 



