Miscellaneous. 339 



It is characterized by the horns being doubly forked, the forks being 

 nearly equal. There is sometimes a small snag on the inner side of 

 the lower part of the beam ; but this is often wanting. The outside 

 of the metatarsus has a large elongated gland. Hoofs triangular, 

 narrow. The skull broad ; suborbital pit large, triangular. The 

 skulls of both sexes are described in my * Catalogue of Ungulate 

 Mammalia in the British Museum/ p. 283. There are two well-de- 

 scribed species found in the "Western States of North America, viz. : — 



1. EUCERVUS MACROTIS. 



Cervus macrotis, Say; Spencer Baird, Marnm. N. A. 657, f. 19j 20 



(horns), t. 23. f. 1 (feet). 

 C. auritus, Warden. 



Rump white. " Tail cylindrical, a little longer than the ears, very 

 slender, naked beneath, except at the end, which is a black tuft." 



2. EuCERVUS COLUMBIANUS. 



Cervus Columbianus, Richardson, F. B.-A. t. 20; Spencer Baird, Mamm. 

 N. A. 659, f. 22, 23 (horns), t. 23. f. 2 (feet). 



?C. Lewisii, Peale. 



Rump like back. "Tail cylindrical, hairy and white beneath, 

 almost entirely black at the base." 



Mr. Titian Peale describes the hoofs of his Mule Deer as different 

 from those of the Black-tailed Deer ; but Dr. Spencer Baird says that 

 the hoofs of both the species he describes were alike and slender ; 

 so that perhaps Mr, Peale' s animal may be a third species of the 

 genus, characterized by the hoof, like the Elk and the Wapiti. 



On the Development of the Myzostoma. By E. Mecznikoff. 



The Myzostoma, parasites of the Comatula, notwithstanding re- 

 peated investigations, still occupy an uncertain position in the zoo- 

 logical scale. The most recent observers, such as M. Semper, seem 

 inclined to approximate them to the Arthropoda. 



The author has arrived at a different conclusion. It is among the 

 AnneUds that he seeks the nearest allies of the Mijzostoma, found- 

 ing this view upon the development of the parasite, which he has 

 been able to investigate partially by the aid of artificial fecundation. 

 The young larva, which is at first ciliated, soon presents rudiments 

 of setigerous pedal rami. Such a larva certainly presents no resem- 

 blance to a Nauplius, nor does it possess the facies of an Acarian or 

 Tardigrade, which has been supposed to be recognizable in the figures 

 given by Semper. 



The Myzostoma would therefore be parasitic Annelids. Their 

 skin, moreover, presents a structure similar to that of Annelids, in- 

 asmuch as its cuticle is set with bundles of vibratile ciHa, a character 

 which is not presented by other classes of worms. The papilhferous 

 trunk of the Myzostoma is hardly to be discriminated from that of 

 the Geryones or Fhyllodocece. Their ramified intestine is merely a 



