448 T. J. EVANS 



The Keprod active System (Text-fig. 2). — The works 

 of Alder and Hancock, Bergh and Trinchese provide an abun- 

 dance of surface views of incompletely dissected reproductive 

 systems of the Aeolidiomorpha, but the complexity of the 

 oviducal glands (ootype) is such that none is satisfactorily 

 described. The attempted reconstruction of the oviduct of 

 Doto fragilis by Dreyer (2) shows how a tangle may be 

 made worse by this method. In Calma, however, the structure 

 of the ootype is so simple that a little displacement of its parts, 

 aided by reference to serial sections, is sufficient to disclose 

 its mode of formation. With the knowledge thus gained as key 

 it was found that the much more intricate ootypes of Aeolidia, 

 Antiopella, and Pleurophyllidia are elaborations of the same 

 general plan. 



As in Aeolidiomorpha generally, the gonadial unit consists 

 of a large central male acinus, bearing a number of female 

 acini, first as solid outgrowths, later as hollow diverticula of 

 its wall. Here, however, the gonadial units (fj.u.) are not as 

 elsewhere united together into a compact mass, but serially 

 distributed in all the interceratal spaces except the first. 

 Thus six to eight pairs are present according to the size of the 

 animal. Paired efferent ducts {e.d.) lead into the spermoviduct, 

 which swells into a coiled ampulla before the bifurcation into 

 male and female ducts at y, Text-fig. 2. The vas deferens {v.d.) 

 is very long, with a thick, glandular wall in its middle portion. 

 All other Aeolidiomorpha have their male and female openings 

 approximated in a common atrium, except Fiona, but the 

 male opening of Calma is placed in front of and below the level 

 of the right rhinophore (see fig. 1), while the female opening 

 occupies the usual position between the first and second ceratal 

 groups on the right. It is curious that, along with this primitive 

 position, the male organ itself has a primitive structure reminis- 

 cent of the Bullids, especially Haminea. It is a partial pleurec- 

 bolic introvert, the penis sac in the retracted condition contain- 

 ing the unchanged apex of the penis as a conical papilla on 

 which opens the vas deferens. Close to the end the deferent 

 duct receives that of a long tubular gland {g.a.) resembling the 



