ON THE DEVELOPMENT OF NEBALTA. 391 



a ganglion in the late larval stage wliicli disappears in the 

 adult, 



Claus places the Leptostraca as one of the three orders into 

 which the Malacostraca are divided by him, namely, Lepto- 

 straca, Arthrostraca, and Thoracostraca. 



In 1892 Grrobben, in a paper on the classification of the 

 Crustacea, pointed out the several points of resemblance 

 between Branchipus and Neb alia, but finally came to the 

 conclusion that it would be harder to join Neb alia to the 

 Phyllopoda than to the Malacostraca. He divided the Mala- 

 costraca into two main divisions, the Leptostraca and the 

 Eumalacostraca, the latter division including the three orders 

 Stomatopoda, Thoracostraca, and Arthrostraca. His paper 

 contains a tree of the Crustacea, similar to that given by 

 Claus (1885), in which the Leptostraca are made to come off 

 from the Crustacean stem with the Protoschizopoda. 



In 1893, Hansen suggested a new classification of the 

 Malacostraca. Like Grobbeu he divided them into two 

 groups, Leptostraca and Eumalacostraca, which latter 

 consists of three orders (unnamed). The first of these 

 orders contains the Mysidje, the Cumacea, Isopoda and 

 Amphipoda; the second, the Euphausids and the Decapods, 

 while the third exists for the Stomatopoda only. He con- 

 siders that the Leptostraca are decidedly the most primitive 

 Malacostraca, and that of the Eumalacostraca the most nearly 

 related to them are the Mysidte. He found in the shaft of 

 the second antenna of Nebalia five joints of which the last 

 showed a tendency to consist of two pieces. This makes the 

 shaft resemble that of the second antenna of My sis. Other 

 points of likeness which he mentions are (1) the develop- 

 ment of the ]arva3 ; (2) the form of the heart ; (3) the fact 

 that young embryos of Mysis have at the hindmost end of 

 the body two small hard processes fairly well chitinised 

 which must be homologous with the furcte in Nebalia; (4) 

 the presence of conical outgrowths at the openings of the 

 male ducts. 



In 1897, Butschinsky published in the 'Zool. Anzeiger' a 



