576 Bashford Dean Memorial Volume 



(14.2 in.) long but no dimensions of the elongate yolk sac are given. The specimen weigh- 

 ed 800 g. (28.2 oz.) of which the yolk alone weighed 500 g. (17-9 oz.) In his figure the long 

 yolk mass extends from the pectorals to beyond the cloaca. 



Since the above was v^^ritten, I find that, unknown to Dean, Lohberger, Shann, 

 Sanzo and myself, a far larger egg and embryo of another Isurid shark had been recorded by 

 VaiUant in 1889. He described but unfortunately did not figure an embryo of Oxyrhina 

 spallanzanii whose total length was "50 cmt." (500 mm., 19.65 in.) on a yolk sac measuring 

 235 X 140 mm. (9.25 x 5.5 in,). Fish and yolk had been more than 50 years in alcohol. 

 Yet, "Le poids total de cette piece, qui represente en somme un oeuf gigantesque de 

 Selacien, est, dans etat actuel de conservation, de 3 kil. 250 gr.'" This weight (3250 g., 

 114.6 oz., 7.2 lbs.) seems incredible hence I have quoted VaiUant verbatim. So far as 

 I know this is the largest egg and embryo of any shark ever described. 



I can not find that the egg capsule of an Isurid shark has ever been figured. Not 

 only does one wish to see an embryo and yolk sac of one of these sharks tor comparison 

 with a like stage oi Chlaynydoselachus, but also for comparison one wishes to see and 

 examine the capsules which enclose the largest eggs in the animal kingdom — eggs much 

 larger than those of the ostrich. 



There is in the Museum collection an egg and embryo of Chlamydoselachus mounted 

 for display on a sheet of glass in a rectangular jar of alcohol. The embryo measures 370 

 mm. (14.55 in.) and the yolk sac 78 x 60 mm. Dismounted, and w^ith the excess of alcohol 

 drained olF, egg and embryo weigh 213 g. (7-5 oz.) Another yolk sac of about the same 

 size (.74 X 60) detached from its embryo w^eighed 142 g. (5 oz.) The little fish, drawn when 

 fresh (Figure 49, plate V), measured 390 mm. and the unhardened yolk 100 x 70 mm., but 

 after being in alcohol for at least 33 years it has shrunk to the dimensions noted above. 

 The weight has also decreased somew^hat. There is much yellow oil in the yolk. This 

 soaks out into the alcohol, which has periodically to be replaced by fresh alcohol. 

 This automatically reduces the weight of the yolk. 



The young frilled shark is a little longer (370 vs. 361 mm.) but much more slightly 

 built, especially in the forward parts, than Sanzo's Carcharodon. The total weights are 

 very different — 213 vs. 800 g.; but after all the greatest difference is in the weight of the 

 yolk sac— 142 vs. 500 g. Here contrast Dean's Chlamydoselachus (Figure 49, plate V) 

 with Lohberger's Lamna (Text'figure 20). 



SIZES OF EGGS OF THE NURSE SHARK 



I have unfortunately never seen the eggs and embryos of Lamna nor Carcharodo7^ 

 but I have studied the encapsuled eggs and early embryos of the nurse shark, Gingly- 



mostoma. ^^nd since these heavy-shelled intra-oviducal eggs are in many ways similar 

 to those of Chlaynydoselachus, some data concerning them m the encapsuled stage will be 

 valuable here for comparison. My figures give lengths and unfortunately girths instead of 

 uridths of the capsules. Furthermore since it was not easy to measure the horizontal 

 diameter of the yolk mass through the thick and oftentimes scarcely transparent capsule, 



