ovoid portion to tlip liend. Both parts of tlie organ are (illcd l)y a pig- 

 mented protoplasm continuous witli tliu liypoderniis. No nerve connection 

 was observed. 



Tlie abdominal vesicle is situated on tlie ventral surface of the first abdom- 

 inal segment. It is cleft longitudinally and the hypodermic cells lining 

 this cleft are glandular in appearance, and are larger than on the outer 

 sides of the vesicle. Pas-sing forward from this point on the ventral middle 

 line of the body to a median cleft in the lower lip, is a small tube, in the 

 formation of which both hypodermis and cuticula take part. 



In the posterior portion of the head are a pair of glands which resemble 

 salivary glands and which I regard as their liomologues here. From these 

 glands a duct leads forward and soon fuses with its fellow, and the median 

 duct thus formed passes along the under surface of the buccal cavity to a 

 median cleft of the under lip, where, instead of emptying into the mouth, 

 it turns downward and joins the ventral tube just described. This remark- 

 able relation of the parts concerned I am unable to explain, although sure 

 that no error of observation was made. Traces of a rudimentary "spring" 

 occur in the fourth abdominal segment. The female reproductive organs 

 are a pair of tubes, the ducts from which join, forming a median duct with 

 a ventral diverticulum — the receptaculum seminis. The structure of these 

 parts and the formitlion of ova is nearly the same as described by Sommer 

 {I. c.) for Macrotoma. 



The number and arrangement of the male reproductive organs is the 

 same as in the female e-xcept that there is no ventral diverticulum of the 

 median duct. In both sexes the external opening of this duct is on the 

 fifth abdominal segment. 



In the immature testis are groups of granules and scattered nuclei. These 

 groups develop, the granules elongate, and form threads lying in bundles. 

 Soon Regeneration occurs, resulting in the formation of a quite homogeneous 

 mass, with scattered nuclei, around which protoplasm collects, forming a 

 sort of epithelium in which fat globules and spermatozoa are formed. 



Lepisma saccharina is larger than Anurida, and has ten abdominal seg- 

 ments. Three anal cerci and several abdominal appendages are present, 

 and the female has in addition a long ovipositor. 



The mouth parts are of the mandibulate type and cannot be retracted 

 into the head. The digestive tract behind the brain gradually enlarges till 

 near the end of the fourth abdominal segment, where it abruptly contracts, 

 and now in its walls six chitinous rods are formed, armed with stout teeth, 

 while the circular muscle layer becomes much developed. Beyond these rods 

 the lumen becomes still smaller and turns dorsally, then suddenly bends 

 ventrally and enters the stomach. This has extending forward from the 

 entrance of the portion just described, six short ca;ca. It passes back into 

 the seventh segment of the abdomen, where it makes a half circle to the 

 left, and joins the ileum which completes the circle, passing dorsal to the 

 stomach, and continues back about one segment when it enters the rectum. 

 The rectum is a large irregularly shaped chamber with many folds and 

 diverticula. It finally narrows and leads by a very short straight tube to 

 the anus. 



The epithelium of the stomach bears a " Hiirchensaum," and in many 

 places forms small crypts, the function of which is claimed by Oudemans 

 to be the formation of new cells. The crypts are certainly suggestive of a 

 glandular function, however. The stomach has no chitinous inlima, but 

 all the other parts of the digestive tract are lined by a cuticle. This is the 

 case in the ileum, from the anterior end of which several Mulpighian tubes 

 are given off. The epithelium of the ileum is thrown into six longitudinal 

 folds. This whole portion is supported by mesenturies passing in various 

 directions, accompanied by muscle fibres. The rectal epithelium is col- 

 umnar and its cell walls stain very faintly. The nuclei lie near the bases 

 of the cells. 



