16 D. BRYCE ON THE MACROTRACHELOUS CALLIDINJ). 



desire to show you that it is important from a higher point of 

 view, viz., that the habits and life histories of various species 

 present to us some very interesting biological studies, peculiar 

 so far as is yet known to this one genus. 



But which are the Macrotrachelous CalUdince ? On page 59 

 of the Supplement Dr. Hudson tells us that Milne proposes 

 the genus Macrotrachela for three-toed PMlodinadcB, having the 

 pre-intestinal part of the body decidedly longer than the post- 

 anal, and that all the species are Callidmce. When this was 

 written Dr. Hudson had probably not seen Mr. Milne's second 

 article (No. 187 of the " Bibliography "), for in it was described 

 a species, Macrotrachela Boejoeri, very similar in habits and 

 general structure to Callidina 7'eclusa, but possessing two dis- 

 tinct eyes within the frontal column, and, .therefore, technically 

 not a Callidina. In this article, and apropos of these closely 

 related species, Mr. Milne again urged the proposition made 

 originally as regards the species now known as Adineta octdata, 

 that Ehrenberg's classification of the FhilodinadcE was unsatis- 

 factory, insomuch as it associated species mani^sstly distant, 

 while separating species as manifestly of a close relationship. 

 To amend the position he proposed in his earlier paper a new 

 arrangement of the genera, and among other suggestions 

 brought forward the new genus Macrotrachela. To my mind 

 this genus associates a very compact group of species, with a 

 decided family likeness, and 1 should much like to adopt it, 

 and to see it accepted, but the scheme involves the primary 

 separation of the Fhilodinadce into those having four toes and 

 those having three toes, a character extremely difficult to detect, 

 and, therefore, a bad one for such a purpose. Without going 

 further into this matter, I have ventured, by the use of the 

 term Macrotrachelous, to avail myself of the most valuable of 

 Mr. Milne's suggestions, to denote those Gallidinoi in which, 

 Avhen fully extended, the post-anal portion is decidedly shorter 

 than the pre-intestinal. 



Three species, jparasitica, socialis, and magnicalcarata, do not 

 possess this character, and these, therefore, do not fall within 

 my subject matter. They have, however, one common point of 

 interest, namely, that all three are ecto-parasitic upon other 

 forms of animal life. 



The remaining species are all Macrotrachelous. Their great 



