188 The American Naturalist. [February, 
of two or three, and the hind-brain of six or five neuromeres, a total 
of ten, which correspond with the line of division between the nine 
mesodermal somites recognized bý Van Wijhe in the head. 
The Origin of the Pelvis.—Wiedersheim, in a preliminary 
account of the origin of the vertebrate pelvis (Bericht d. Naturf. Gesell- 
schaft, February, IV., 1889), claims that the key to the first appear- 
ance of this structure is to be found in Lepidosiren annectens. Here the 
fibrous tissue of two pairs of myotomes in front of the cloaca through 
a process of chondrification reach a higher condition of connective 
tissue. These cartilaginous zones fuse in the “nea alba abdominis to 
form an unpaired plate, thus affording a solid support for the free ex- 
tremities. This process, which occurs again ontogenetically in the 
lowest urodele Batrachia, finds a parallel in the chondrification of a 
number of myotomes in the thoracic region of certain perennibran- 
chiate Batrachia, —ż.e., in the rudiments of hyaline cartilage ventral 
ribs. The sternum of the Batrachia also falls in the same morpho- 
logical category. 
The vertebrate pelvis also owes its first appearance to the conversion 
into cartilage of a pair of abdominal myotomes—or to use the terms 
of human anatomy, of the inscriptiones tendinee of the ventral body 
muscles, 
The Stapedial Bones.—Dr. C. K. Hoffman claims (Zool. Anz., 
310) that the stapes in the reptiles arises from two sources. The oto- 
stapes arises from the outer layer of periotic mesoderm as a strong 
lateral process. At about the same time the hyoid arch is prolonged 
into a medial projection, the hyostapes, which unites with the otostapes 
to form the stapes, while the connection with the hyoid is lost. Hoff- 
man thinks that similar relations can be traced in the Mammalia. The 
stapes proper is the otostapes, and the os lenticulare is the hyostapes. 
The fact that the facial nerve innervates the stapedial muscle on the 
lenticular portion lends probability to this view. 
Frogs Eating Snakes.—(January Naturauist, p. 74). If Mr. 
H. L. Roberts will turn to page 348 of my ‘ Naturalist’s Rambles 
About Home,”’ he will find that I have described in full an instance of 
a frog (Rana pipiens) swallowing a snake. More recent observations 
have convinced me that such an occurrence is not as uncommon as 
might be supposed, considering the fear usually exhibited by a frog 
when a snake —— ONR C. ABBOTT, Trenton, N. J. 
