NEW MAI.I.OPHAC. A. 175 



Ho turthcr describos the maiuier in which the diireieiU 

 parts of the heart and aorta conlrael, and also gives an 

 account of the mctliods he used in niakin;^ his observa- 

 tions. Finally he states that lie examined several rep- 

 resentatives of the Philopteridie, such as LipcuruH cart- 

 abilift, Ooniodes colchici, and JJocojihoruK iitraivf<, but 

 apparently he determined merely that the heart is pres- 

 ent in these forms. 



\\ . T H E K E !• K O D U C T 1 \' E U K G A N S. 



The reproductive organs of both the male and the 

 female may be divided ontogenetically into (1) parts 

 derived from the interior of the body, including the 

 testes or ovaries, the vasa deferentia or oviducts, and 

 the vesicula scminalis, ejaculatory duct or vagina and 

 spermathieea; and (2) into i)arts derived from the 

 exterior of the body, including a genital cavity in both 

 sexes, and an eversible penis witli variously developed 

 accessory ohitinous parts in the male. According to 

 Nusbaum (1882) the embryological origin of the internal 

 organs of fjpeurus bacillus and Goniocotes holoyuMir 

 is as follows : The parts arise from four fundaments. 

 Two of these are derived from the mesoderm and give 

 rise to the testes or ovaries and the vasa deferentia 

 or oviducts; the others are derived from the epiblast of 

 the ventral side of the fourth abdominal segment, and 

 give rise to the vesicula seminalis and ductus ejacula- 

 torius of the male or the vagina and spermathieca of the 

 female. The second pair subse(iuently unite forming 

 the unpaired organs of the adult. The latter are hence 

 strictly external since they originate from the epiblast 

 of the embrvo. For convenience of descri|)tion. how- 

 ever, the parts are classilied better as internal and 



