6l6 Bashford Dean Memorial Volume 



effective help of Prof. Mitsukuri ot the Imperial University of Tokyo to the end that all 

 specimens of Chlamydoselachus taken in the Gulf of Tokyo should be reserved for him 

 (Dean). Hence one may judge that the fish had been taken by the fishermen to the Depart- 

 ment of Zoology in the University, there opened and the embryos secured for Dean. 



The original drawing (Figure 49, plate V) measures 382 mm. between perpendiculars, 

 and the yolk sac is 92 x 70 mm. If the fish was drawn alive or just dead, the discrepancy 

 of 8 mm. between its length and that of the largest of the four embryos Usted above 

 (390 mm.) may be disregarded, as it may for the discrepancy in yolk measurements (92 x 70 

 in the figure vs. 100 x 70 mm. in the notes"). These may be errors of the artist. But I have 

 shov.Ti earlier in this paper that embryos brought up within the mother from a depth of 

 300 to 500 fathoms, from a region of great pressure and low temperature, to the University 

 of Tokyo in May, could only have survived a few minutes. Here then is what I judge to 

 have been done when this specimen came in. A quick sketch in color ■w.'as made while 

 embryo and yolk were fresh. Then to preserve it, the fish u^s put in formalin (which 

 bleaches out color less than alcohol). Later, and as soon as possible, the completed draw- 

 incr was made — the size from the specimen in preservative, the color from the hasty color 

 sketch. The embryo in preservative for a month would easily have shrunk 8 mm. The 

 shrinkage of 8 mm. in the length of the long axis of the yolk is entirely within the limits 

 as I have observed it in the large yolks of other fishes. To strengthen this case it may be 

 noted that among Dean's frilled-shark materials there is a water-color sketch of the 

 reproductive organs of a just-opened female Chlamydoselachus evidently intended as 

 the basis of a figure in natural color. Unfortunately this drawing was never made or has 

 been lost. But we do have here this beautiful drawing showing this late embryo, the 

 yolk sac, and on the side of the egg the yolk-sac circulation, all in their natural colors. 



There is in the Museum collection — it stands before me as I wTite — what I believe 

 to be the very specimen from which the drawing (Tigure 49, plate V) was made. The 

 shape of the head and mouth, the fold across the snout above the upper jaw, the form and 

 position of the gill-sUts, the upturned pectoral fin, the form and position of the other fins 

 and the tail, the irregularities in the lateral line, the shape and position of the yolk sac — all 

 are practically identical. This is surely the fish from which the drawing was made. The 

 fish, after at least 33 years in formalin and alcohol, measures 370 mm. in total length and 

 the yolk mass 78 x 60 mm. But those who have had to do with specimens in preservative 

 know that this decrease in the size of the fish is not beyond limits. However, the yolk has 

 undergone even greater shrinkage than the fish. The ordinary fish -egg yolk shrinks con- 

 siderably in presen-'ative, but there is in the egg yolk of Chlarnydoselachus an additional 

 factor in its shrinking. There is in these yolks an unusual amount of oil which is dissolved 

 out by the alcohol. This alcohol, even to this day, has to be changed frequently. This 

 dissoh-ing of the oil aids materially in the diminution of the volume of yolk as it hardens. 



The likeness of this 15.35-inch embryo to an adult is close both m the general mor- 

 phology and in the details. The mouth, reaching far back of the eye, is almost terminal 

 and evidently has a great gape. There is the groove marking off the cartilage of the upper 



