572 GEOLOGICAL SURVEY OF THE TERRITORIES. 



EXPLANATION OF PLATE XXIX. 



Fig. 1. Estheria mexicana Glaus, from Kansas {E. caldwelU); first antenna ; ol, olfac- 

 tory lobes ; at, n, antennal nerve. 



Fig. la. Terminal joints of the same, filled with olfactory cells ; no papillas present. 



Fig. 1&. Olfactory lobes from near the middle of the antenna. 



Fig. 2. Estheria mexicana {caldwelU) ; three terminal joints of the second antennae, 

 showing the nerve-endings and the sense-cells at the base of the setae. 



Fig. 3. Estheria compleximanus, edge of sixth endite (of PI. V, fig. 7), showing the 

 ends of the tactile nerves leading to base of tactile setae and connecting 

 with the marginal nerve; with the two series of independent nerve or 

 ganglion cells, X 225 diameters. 



Fig. 4. Estheria compleximamis Pack. ; end of the dorsal lobe or oviger of one of the 

 anterior legs (figured on PI. V, fig. 7), showing the tactile nerve (tn) with 

 its ganglionic enlargement near and at the end of the lobe ; with the gan- 

 glion cells at the base of the setae. 



Fig. 5. Estheria compleximanus, end of 5th endite of Ist leg (PI. V, lig. 5), showing the 

 very large crowded ganglionic tactile cells (gc). 



Fig. 6. Branchipus vernalis Verrill. End of 1st antenna, with the three tactile setae at 

 the tip; n, antennal nerve; gc, ganglion cells, X iA. 



Fig. 7. Thamvocephalus platyurus Pack. The 3d or 4th endite of the 1st foot, with n 

 the nerve to the endite, the large ganglion cells arranged in quite regular 

 series, and tn the origin of a tactile nerve passing into the seta (s) ; each seta 

 is about to moult, as the new setae with the fine setulae are present. 



Fig. 8. Thamnocephalus platyurus Pack. Portion of the edge of 1st or innermost endite 

 of 1st pair of feet ; w, nerve-fibres; grc, ganglion cells ; to, tactile ners'es pass- 

 ing into the long, slender seta3 (s), near tn, the marginal row of tine setae. 



Fig. 8 a. Thamnocepholus platyurus Fack., Cuticleofflabellum with nuclei (») and tine 

 tubercles. 



Fig. 8b. Thamnocephalus platyurus Pack. Cells at base of 5th endite containing fat 

 granules. 



i'lG. 9. Limnetis gouldii. One eye with the cornea removed, the same specimen as repre- 

 sented on PI. II, fig. 5. Op. n, optic nerve; the upper op. n. shoitld be op. g, 

 optic ganglion. From the peripheral nucleolated cells the nerves with the 

 rods (if the latter are present) converge towards the optic ganglion; tr. m, 

 transverse nerves arising fi'om peripheral cells and connecting the two eyea. 

 A.11 the figures drawn with the camera lucida by the author. 



