ON THE DEVELOPMENT OF NEBALIA. 425 



no maxillary glands, these latter had not yet appeared, 

 and that, therefore, the antennary gland in My sis, as in 

 Neb alia, develops before that of the second maxilla. A 

 maxillary gland has not yet been recorded for the adult 

 My sis. There can be no doubt that the glands on the 

 thoracic legs in Nebalia, in spite of their alkaline reaction 

 (Kowalewsky and Metschnikoff, 1899), are morphologically 

 equivaleut with the glands in the same position in Mysis, 

 kSquilla, and other Malacostraca. 



As far back as 1868 Metschnikoff suggested that, in a 

 classification of the Crustacea, Nebalia should be placed by 

 the side of the Schizopods. Since then, as can be seen in 

 the historical section of this paper, other observers have 

 from time to time noted the likeness of Nebalia to the 

 Schizopods or the Mysidas. Claus (1886) and Grobben (1892), 

 in their schematic trees (which differ only as regards the 

 Stomatopoda) make the Lepostraca come off from the Proto- 

 malacostraca with the Protoschizopoda. In the present state 

 of our knowledge this arrangement perhaps shows the rela- 

 tionship between Nebalia and the other Malacostraca better 

 than any other, for the Mysidfe are undoubtedly the most 

 primitive Schizopods. 



The classification of the Malacostraca by Grobben (1892) 

 and Hansen (1893) into Leptostraca and Eumalacostraca, and 

 the division of the Schizopoda by Boas (1883) and Hansen 

 (1893) also make apparent the nearness of the Mysidee to the 

 Leptostraca; but Caiman (1904) in his amplification of 

 Hansen's classification of the Malacostraca seems to have 

 masked this nearness. He has done this by the introduction 

 of Anaspides into the Eumalacostraca. We know very 

 little about this animal, and nothing of its development. 

 Judging from the account of its internal organs given by its 

 discoverer (Thomson, 1894) it would seem to differ so much 

 from the other Crustacea as to warrant its not being given a 

 place at least until some well preserved specimens have been 

 examined. 



