Salivnry glands of a simple niiture :inil with no noteworthy fciiturcH, are 

 present. The fat Iwdy is apparently of the name struoliiro as in Annrida. 

 The heart leads forward into an aorta, which in the prothorax bends 

 downward from the dorsal surface of the body till it touches the a'sophagus. 

 It does not enclose this but soon becomes lost. The heart at its [KMiterior 

 end is wide open, somewhat like tlie mouth of a trumpet, anterior to which 

 point it becomes small, and with very muscular walls. About two abdom- 

 inal segments farther forward it iiuite rapidly enlarges till iU lumen is 

 seven or eight times as large as it was before, while the walls becoiue thin- 

 ner. The heart between here and the aorta has its usual structure, with 

 oslia, none of which were observed in the muscular portion. 



A tracheal system is present, but I failed to ascertain its exact distribution. 



The nervous systeru con.sists of a brain, sub-oesophageal ganglion, three 



thoracic and eight abdominal ganglia. Of the.se the last thoracic and first 



two abdominal ganglia, and the seventh and eighth abdominal ganglia are 



partially fused. 



The brain is more complicated than in Anurida, calyces being jirescnt. 

 No trace of the large nuclei at the origins of the main nerve trunks, was 

 found. 



Each eye consists of twelve facets or ommalidea. Each ommatideum 

 consists of a large cornea, beneath which are two corneagen cells. The 

 crystalline cone lias the form of a concavo-convex lens, and just lateral to 

 it are the four cells of the vitrella. 



The rhabdomere is pyramidal, its base resting against the internal face 

 of the crystalline cone. Surrounding it are four retinulae which are densely 

 pigmented and the pro.ximal ends of which perforate the basement mem- 

 brane and become optic nerves. The ommatidea on the whole somewhat 

 resemble those of Scrolls. Between them are packed pigment cells. 



The position and structure of the reproductive organs of both sexes is 

 much the same as in Anurida. 



Lepisma s"feems to represent about the highest grade of differentiation yet 

 attained by the Cinura, while Anurida seems to have undergone a differen- 

 tiation perhaps even greater, but followed by a degradation, probably cor- 

 related with a change of habits and food. The internal anatomy of the 

 Thysanura as a whole appears to confirm the Campodea theory advanced 

 by Braur. 



