334 Miscellaneoiis. 



seems conceivable that a spermatozoon of an earlier male, whicli 

 was for anj' reason unable to produce a perfect embryo, might enter 

 an ovum without destroying it or causing it to develop, and that 

 the ovum might afterwards be fertilized by a perfect spermatozoon 

 of another male, and develop accordingly. The germ-plasm derived 

 from the first and apparently ineffectual spermatozoon would account 

 for the result as recorded, and the hybrid or mongrel animal would, 

 in fact, have two fathers. 



This is hypothetical, of course ; but, while waiting for further 

 proof, it may be permissible to set hypothesis against hypothesis. 



T. D. A. COCKERELL. 



Las Cruces, New Mexico, U.S.A., 

 Aug. 3, 1893. 



On the Identity of the " Cotton Spinner " (Holothuria nigra) of 

 English Authors loith Holothuria Forskalii, Chiaje, and on the 

 Occurrence of Cucumaria Koellikeri, Semp.^ in the Atlantic Ocean. 

 By Dr. Emil von Maeenzeller, 



The following observations were evoked by the examination of 

 certain Holothurians which were collected off Sines, on the coast of 

 Portugal, and for which I am indebted to the kindness of Prof. 

 Paulino d'Oliveira, of the University of Coimbra. The collection 

 comprised specimens of Holothuria Forskalii, Chiaje, Cucumaria, 

 KoelliJceri, Semp., and Cucumaria Montagui, Flem. 



Holothuria Forshalii (to which species Ludwig justly assigned 

 //. cataniensis, Gr.) was first shown to exist in the Atlantic Ocean 

 in the year 1882 by Greeff. The author referred to found the 

 species in Setubal Bay, while in 1890 Herouard reported it as 

 occurring at PLOscoff. This Holothurian, which is characterized by 

 its external appearance, by the slight development of the calcareous 

 bodies, and the possession of Cuvierian organs, had, however, 

 already been observed long before on the British coast, especially 

 in the West of Ireland, and had been designated "the Nigger 

 or Cotton Spinner" (Holothiria nigra). Anyone may convince 

 himself of the justice of this view by comparing the calcareous 

 bodies of H. Forslxdii with the figures of these structures in H. nigra. 

 given by Jeffrey Bell (' Catalogue of the British Echinoderms,' 

 London, 1892). For my part I was also able to compare prepara- 

 tions of calcareous bodies furnished to me by the Eev. Canon A. M. 

 Norman, and derived from a specimen of //. nigra from Polperro, 

 Cornwall. That this state of affairs, which is interesting from the 

 point of view of animal distribution, remained so long undiscovered, 

 is probably to be ascribed to the insufficiency of the earlier descrip- 

 tions of H. nigra, as well as to the fact that the animals themselves 

 did not come into the hands of those investigators who were 

 acquainted with H. Forskalii. Moreover, Stichopnis Selenhv, de- 

 scribed by Th. Barrois in 1882 from Coucarneau, is certainly nothing 

 else than H. Forshalii. The difference shown in the representation 

 of the calcareous bodies will receive correction. It appears that in 



