530 Miscellaneous. 



In the possession of two separate sexual openings CavoUnia lonr/i- 

 rostris differs from all other Pteropods. The opening on the right 

 side leading to the penis is perhaps to he homologized with the 

 single aperture of other species. All that is necessary is the closure 

 of the usual ciliated groove to form a tube to the penis, and this is 

 an evident advantage in ensuring the transference of the male 

 products. Another o])ening (vagina) becomes a necessity as soon as 

 tlie more primitive right one is given over entirely to the male 

 products ; and this may account for the new aperture on the left 

 side. In other words, the other Pteropods represent the more primi- 

 tive condition of the hermaphroditic duct, while Cavoliala lonqirostris 

 has become more specialized l)y the accpiisitiouof a separate opening 

 for each sex. The anatomy of the adult does Tiot, of course, show 

 whether, as Korscheldt and Heider (' Lehrbuch der vergleichendea 

 Entwicklungsgeschichte der wirbellosen Thiere,' p. 108.S, fig. 044 o) 

 would put it, there has been a splitting of a primitively single 

 opening into two, or whether a new independent opening has been 

 acquired into the left side of the uterine gland. Perhaps the study 

 of the ontogeny of the sexual organs of this species will settle the 

 question. 



Contrary to Pelseneer ('Challenger' Iteport on the Pteropoda, 

 pt. 3, p. 19), the heart of CavoUnia lonr/irostris is on the left side, 

 agreeing with Souleyet's figure of CavoUnia tridentata, for which 

 see Lang (' Lehrbuch der vergl. Anatomic,' p. 604, fig. 409). 



Muscles in the fins are distinctly striated, a condition which Lang 

 states (' Lehrbuch der vergl. Anatomic,' p. 095) is not found in 

 mollusks, but which Kellogg (" A Contribution to our Knowledge 

 of the Morphology of Lamellibranchiate ^lolluscs," Bull. U.S. Fish 

 Commission, vol. x. 1890) found in tlie adductors and heart-muscles 

 of Lamellibrauclis. Paneth (' Archiv mikr. Anatomic,' Bd. 24), 

 describing a similar appearance in the fins of Ci/mhulia and Tiede- 

 mannia, decides this is not natural, but artificial striation. I have 

 not been able to study living tissue, but the striation, as I find it, 

 is very distinct, and looks in every way like ordinary striated 

 muscle. — Johns I/o2jl'ins Uaivevsity Circulars, May 1894, pp. 01, 02. 



