200 DISCOVERY REPORTS 



of the Bingham Oceanographic Collection, and a check on the Bermuda series (Pickford, 1950) shows 

 that here also the oral face is brown. It was therefore a surprise to find that the oral face of the web is 

 black in the nine Discovery specimens which are preserved in alcohol. Presumably in life it may even 

 have been purple. An exactly similar observation was made on the Indian Ocean specimens taken by 

 the ' Galathea '. Five of the Discovery specimens are from the Atlantic Ocean and we may therefore 

 exclude the possibility of zoogeographical differences. 



Table 1. List of specimens, dates of capture and summary of distribution 



* Author's register of known specimens. Nos. 1-77 are listed in the Dana Reports (Pickford, 1946, 1949a), Nos. 7S-95 

 in The Vampyromorpha of the Bermuda Oceanographic Expeditions (Pickford, 1950). 

 f Designations of basins from Sverdrup, Johnson & Fleming (1942). 



Unpublished histological studies on the pigment cells of Vampyroteuthis have shown that the 

 black pigment is in the form of rather large, spherical granules whereas the red-brown pigment is in 

 the form of much smaller and more irregular granules that tend to clump in little aggregations, giving 

 an appearance of reticulation to the chromatophore. Clearly there are physical if not chemical 

 differences between the black and 'brown' chromatophores but it is possible that the latter only 

 assume their brown colour after certain methods of preservation. We cannot escape from the fact 

 that in life, and in alcohol preserved specimens of the Discovery collections, the oral face of the web 

 is black. 



Mantle length. The observed mantle length of the specimens is given in Table 2, except for specimen 

 No. 96 which was too badly damaged for measurement. The larva of Vampyroteuthis goes through 

 a complicated double metamorphosis in which the posterior or larval fin reaches a length of about 

 5 mm. and is then resorbed, while an anterior (adult) fin develops in smoothly co-ordinated functional 

 adjustment (Pickford, 1949 a). The developmental stages are defined in terms of the presence or 

 absence and relative lengths of the two pairs of fins. It has further been shown that each develop- 

 mental stage is associated with a characteristic range of mantle length. But the mantle length of 

 several of the Discovery specimens appears to be in poor agreement with the developmental fin stage. 

 An attempt has therefore been made to deduce a corrected estimate of mantle length from measure- 

 ments of the eye diameter and of anterior fin length. The estimates are based on a previous investiga- 

 tion of the relationships between mantle length and other bodily proportions, given in the article 

 cited above. These estimates of corrected mantle length are given in Table 3. It will be seen that, in 

 general, the estimates are in good agreement with actual observation. However, specimen No. 101, 



