596 MORPHOLOGICAL METHOD AND RECENT PROGRESS IN ZOOLOGY. 



that the cartilaginous cranium, like the bony one which in the hio'her 

 vertebrate forms replaces it, is in its essence compound. 



I now pass to the invertebrata. Of the Oligocha^ta and Leeches I 

 have spoken, and we may next consider the Arthropods. Of the 

 Insecta our knowledge has gained precision by the conclusion that 

 the primitive number of their Malpighian tubes is six, and b}^ the 

 study of development of these in the American cockroach Doryphora^ 

 which has rendered it proba])le they may be modified nephridia, carried 

 in as are those of some oligochivtcs with the proctodeal invagination. 

 An apparent cervical placenta has been discovered in the orthopteran 

 Ileini'inerm^ which would seem to suggest homology with the so-called 

 "trophic vesicle" of the Peripatoids, as exemplified by P. Novse- 

 Brltannica. In this same orthopteran there have been recognized, 

 in secondary proximity to the "lingua,"' reduced maxillula^, which, 

 fully developed and interposed between the mandible and first maxilla, 

 in Japyx^ Mavldlh^ Forficida^ and the Ephcincra larva, give us a fifth 

 constituent for the insectan head. And when it is found that all the 

 abdominal segments of the conn'non cockroach, when young, are said 

 to bear appendages, of which the cerci are the hindermost, we have a 

 series of facts which revolutionize our ideas. Little less striking is 

 the discovery that in the caterpillar of the liombycine genera Lagan 

 and Chrysoj)yga seven pairs of pro-legs occur. 



The fuller study of the apertures of the tracheate body has resulted 

 in the discovery that the Chilopoda are more nearly related to the 

 Hexapoda than to the Dij^lopods; wherefore it is proposed to reclas- 

 sify the Tracheata, in accordance with the position of the genital 

 orifice, into Pro- and Oj)istJiO-gonata. In a word the "Myriapoda," 

 if a natural group, are diphyletic. 



Our knowledge of the Peripatoids {Arfhropoda vialacopoda) has 

 increased in all that concerns distriliution and structure. The}^ are 

 now known, for example, from Africa, the West Indies, Australia, 

 and New Zealand, and for examples from the two latter localities and 

 Tasmania the generic name Oojyei'ijx'dns has but lately been proposed, 

 to include three species, characterized by the possession of an ovi- 

 positor, of which two have been observed to la}" eggs. 



Work upon the Crustacea in our own land, notorious for the ten 

 dencies of some of its devotees in their stickling for priority, has 

 within the last twelve years advanced beyond all expectation. Much 

 of our literjiturc has been systematized, and an enormous increase in 

 our knowledge of new forms has to be admitted, thanks to memoirs 

 such as those of the "Investigator,'' "Naples Zoological Station,'' and 

 others which might be named; while in the discover}' and successful 

 monographing, in the intervals of six years' labor at other groups, of 

 a new family of minute Copepods (the Choniostomatida^), parasitic on 

 the Malacostraca, eml)racing forty-three species, difficult to find, we 

 have an almost unique achievement. The hand w^hich gave us this 



