530 JOSEPH STAFFORD, 



where these canals are full of yolk-cells and it is still more favorable 

 if the animal happens to be young and the follicles few and small. 

 Then the longitudinal, follicular duct shows as a serpentine, irregular 

 tube, widening to receive the necks of folUcles and contracting where 

 there are no contents, till invisible as a definite canal. 



The longitudinal canals were not seen by Voeltzkow, who thought 

 the transverse canals branched into a number of twigs that extended 

 to the vitelline glands, arranged in a longitudinal row on each side. 

 There is no such a structure as he figures. 



It is interesting to find in Diesing's "Asi)idogaster limacoides etc." 

 (1835) fig. 7 and 12 vitellaria fairly well represented, although 

 DiESiNG took them for ovaries. Von Siebold first recognized (1848) 

 that these organs produced only yolk spherules ("Dotterkörperchen"). 



From the description already given, and from the partly diagram- 

 matic figure, it will be clear that the Laurer's canal lies slightly 

 on the right from the middle vertical plane of the body. It is in a 

 direct line with the tuba whose true continuation however is the 

 ciliated portion of the oviduct. The meeting place of the three canals 

 assumes an isosceles-triangular form. It is as if the Laurer's canal 

 widened out gradually and then split into two canals — the tuba and 

 the ciliated portion of the oviduct. Before continuing the description 

 of the Laurer's canal it belongs here to consider the purpose of the 

 parts meeting in the triangular space (Fig. 16 TS). 



Cilia, in the oviduct, were discovered by Huxley (1856), and 

 were seen by Pagenstecher (1857). The ciliated triangular 

 space (dreieckiger Raum) was thought by Voeltzkow to be the 

 ootype (p. 269 — 270), and he also supposed that the walls of the 

 oviduct supplied the place of a shell gland (p. 271 — 272). Now that 

 these organs are accurately localized, and it is shown that the 

 ciliated portion of the oviduct is not the ootype, it is a question of 

 interest: what is the function of the cilia? 



Cilia act from the vitelline duct to the triangular space, from the 

 end of the fenestrated tuba to the triangular space, all along the 

 walls of this latter , and for a short distance into the narrowing 

 Laurer's canal. I have seen cases where the cilia in the Laurer's 

 canal acted in the opposite direction to what I have just stated, i. e. 

 their motion was towards the tuba. Having, some time ago, clearly 

 observed the direction of ciliation I troubled myself no more about 

 it until lately, when I found it was possible for those in the Laurer's 

 canal and tuba to be irregular in their action. It has been impossible 



