REPORT ON THE SCHIZOPODA. 9 



The suborder Schizopoda, as far as at present known, may be divided into four natural 

 sections or families, viz., the Lophogastridse, Eucopiidae, Euphausiidse, and Mysidse. 

 These families are comparatively well defined, exhibiting on the whole very marked 

 differences, both in the external appearance and in several of the anatomical details, and 

 also partly in development. 



The most highly organised Schizopoda are undoubtedly the Lophogastridae, whereas 

 the lowest forms are comprised within the family Mysidae. The Eucopiidae would appear 

 on the whole — notwithstanding the peculiar structure of the legs — to be those most 

 nearly related to the Lophogastridae. Somewhat more divergent are the Mysidae, which 

 form an exceedingly rich and at the same time well-defined group of Schizopoda. The 

 fourth family, the Euphausiidse, occupies in many respects rather an isolated position 

 within the suborder ; thus, the many remarkable pecuharities distinguishing these forms 

 have led Dr. Boas^ to exclude them wholly from the Schizopoda, and to establish for 

 their reception a perfectly distinct order, which, in the opinion of that author, is the 

 one most nearly allied to the remarkable and anomalous Crustacean Nebalia. Although 

 in most points I fuUy entertain the views set forth in the very interesting treatise of 

 Dr. Boas on the affinity of the higher Crustacea, and also admit the significance of the 

 divergencies distinguishing the Euphausiidae from both the Mysidae and the Lopho- 

 gastridae, I am by no means prepared to agree with him in excluding these families 

 from the Schizopoda. In their whole external form and appearance they are true 

 Schizopods, whereas in these respects they do not show any resemblance to the genus 

 Nebalia. This form, too, in my opinion ought to be retained within the order Branchio- 

 poda, representing there, however, a separate section or suborder (Phyllocarida), which in 

 some respects exhibits a perplexing affinity to higher types of Crustacea. 



1 Studieii iiber die Verwandtscliaftsbeziehungen der Malacostraken, loc. cit. 



(ZOOL. CHALU EXP, — PART XXXVU. — 1885.) Oo 2 



