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Bashford Dean Meinorial Volume 



salts and possibly other food substances as well. The rich plexus oi vitelline capillaries 

 will also be bathed in the fluid of the uterine cavity and they may absorb some food and 

 oxygen from it. If this takes place in Chlamydoselachus, it must go on tor a long time, 

 until and even after the yolk, shown m the colored Figure 49, plate V, is resorbed, and 

 this yolk must be used up before the fish is born, else the free oceanic life ot this little 

 shark would be very brief. 



THE CLOAC.\L OPENINGS 



As has been shovv'n, the oviducts at their anterior ends have openings into the ab- 

 domen to receive the eggs set free from the ovaries. So, posteriorly the oviducts have 

 openings into the cloaca through which the embryos, having used up their yolk masses m 

 development, pass out to take up their free life in the sea. The lower end ot the uterus 

 progressively diminishes in size until, as a tube considerably reduced in cross-section, it 

 opens out on the dorsal side of the cloaca. But even here, as everywhere else in this 

 primitive shark, are found some surprising and interesting variations. 



Right Cloac.^l ChTDuc^L Opekixg PREi>Oi!rs-.A>.T 



Since the right oviduct is predominant, since its uterine portion carries the develop- 

 ing young, and since these must pass out through its opening into the cloaca, one would 

 expect to find that the right opening is larger and is possibly somewhat centrally placed. 



Hawkes (1907j first and very briefly refers to the relative sizes of the oviducal 

 openings into the cloaca thus: "The opening of the right enlarged oviduct ... has 

 acquired a median position, the left oviducal opening . . . lymg cephalad to it"". Only 

 this, but she gives a diagrammatic figure to make these relative positions clear — Text- 

 figure 17 herein. Demega (1925; confirms Hawkes and writes at length. Thus he says 

 "The right oviduct opens out by a large orifice in the middle of the cloaca" — as is shown 

 in Hawkes's figure. Of the opening of the left oviduct he ^^nrites more fully "The left 

 oviduct opens in the dorsal wall of the cloaca, rather far in front, so that it makes an im- 

 pression as though it opens into the posterior section ot the right oviduct; this orifice 

 appears in the form of a cross fissure". 



Text-figure 17 

 Diagrammatic figure of the cloaca of 



a female Chlamydoselachus. 

 A. P. closed abdominal pore; L.Ov., lert 

 oviducal opening; R., rectum; R.G., opening 

 of rectal gland into rectum; R.Ov'., right 

 oviducal opening; VS., urinary sinus (the 

 other sinus is omitted); U.S. 1, openings of 

 urinary sinuses into cloaca. 

 After Hawkes, 1907, p. 476. 



