The Embryology of Chlamydoselachus 



575 



and table of measurements of his own four embryos are so involved that I can make out 

 little about them. He had four embryos measuring 10.25, 18, 18.5 and 24 inches respec 

 tively and all in about the same stage of development. His detailed yolk'sac measurements 

 are unintelligible to me — one wishes for diameters such as those given above. Shann 

 states that one of the largest embryos he examined "was a female measuring 21.75 inches 

 and the yolk sac was still of enormous bulk". This is confirmed by his roughly^drawn 



Text-figure 20 



Egg and embryo of an Isurid shark (Laynna sp.) obtained in the Sagami Bay by Franz; Doflein 



C.1905. The embryo was 553 mm. (21.8 in.) long. The yolk sac measured 211 mm. (8.3 in.) x 123 mm. 



(4.8 in). The whole weighed 2.68 kg. =5.9 lbs. 



After Lohberger, 1910, Fig. 1, pi. I. 



figure which shows that the word ''enormous" is correctly used. The yolk reaches almost 

 from the angle of the jaw to the base of the caudal fin. He judges that at birth the young 

 fish would be approximately 30 inches from tip to tip. 



Other Isurids have large embryos on huge yolk sacs. Two cases will be indicated. 

 Sanzo (1912) figures and describes from the Mediterranean the intra-uterine embryo of 

 Carcharodon rondeletii, the great white shark or ''man-eater". The embryo was 361 mm. 



