MOLLUSCA GASTEROPODA. 427 



regards them as biliary ducts which open singly into the 

 stomach. He also gives a different account of the position 

 of the anus and of the genital apertures. In Act aeon the 

 anus is not placed posteriorly in the middle, but anteriorly, 

 on the right side, in the form of a minute papilla, and the 

 genital orifice is not in common, but in the female is 

 situated on the right in form of a minute fissure, which 

 runs from the anus towards the under surface of the animal ; 

 in the male the opening is also situate on the right side 

 at the base of the tentacle. 



It follows of course that Quatrefages should defend him- 

 self against such an attack. (Comptes rendus, xix, p. 806.) 

 He allows that separate genital apertures exist in Venilia, 

 and at the time of copulation, also in the Tergipedina, also 

 that the branchial appendages are perforated at the point. 

 But with respect to the latter he thinks that they are not as 

 it were supplementary anuses, but that they serve for the 

 ejection of spiculce, which correspond in almost all respects 

 with those of the Actinise, Medusae, and Synaptse. On the 

 other hand he denies that the branches of the intestinal 

 canal open singly into the stomach, and that they are 

 biliary ducts, because he has observed the food enter and 

 again leave them ; he also denies the existence of veins. 



Another attack upon the observations of Quatrefages, and 

 written in a much more peaceable style than the above by 

 Souleyet, appears in the Annals (xiv, p. 125), by Joshua 

 Alder and Albany Hancock. The authors regard the genus 

 Eolidina as identical with Eolis. They look upon the 

 absence of the anus, of the male iutromittent organ, and of 

 the complete circulatory organs as the fruits of inaccurate 

 observation. In conclusion, they express the opinion that 

 Quatrefages has been very premature in instituting his 

 division of the Phlebenterata. After all that has been said 

 for and against the Phlebenterata, I feel myself compelled 

 to say that precise inquiries as to the history of the 

 development of these animals are highly desirable. At all 

 events they must constitute a separate division (family), 



