No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 715 
exactly the position of ventral arches, and structures resembling 
them in every respect in larvae of Salamandra maculosa are 
considered by Goppert (No. 47, p. 444) as probable remnants 
of such arches. They are also, almost unquestionably, the 
homologues of the two little bony processes described by 
Goppert on the ventral surface of the body vertebrae of Cala- 
moichthys (No. 48, p. 150). These processes in Calamoichthys 
become, in the tail, the basal processes (Basalstiimpfe) of the 
haemal arches, the remaining, distal portion of those arches 
being formed by the “ Pleuralbogen,” or lower ribs, the haema- 
pophyses, therefore, of Baur, which shift from the under surface 
of the lateral processes onto the distal ends of the ventral 
ones. In the trout, in marked distinction to Calamoichthys, 
no such shifting process takes place (No. 48, p. 187). The 
lower ribs, or Pleuralbégen, in that fish, simply disappear, and 
the haemal arches are formed by direct and independent growth 
from the ventral surface of the base of the Basalstiimpfe, the 
parapophyses of Baur. Judging simply from Schmidt’s figures, 
Amia must agree with the trout in this respect. The haemal 
arches in the tail of Amia would then be homodynamous with 
the ventral processes found on the trunk vertebrae, and with 
those processes only. The ribs would then take no part in the 
formation of the haemal arches in Amia, contrary to what 
Goppert states to be the case in all ganoids excepting Calamo- 
ichthys (No. 48, p. 153), and would agree with those of teleosts 
(No. 48, p. 161). The ribs in Amia may, therefore, be the 
homologues of the upper ribs of Calamoichthys, and not of the 
lower ones. If this be so, the ventral processes in Amia are 
the parapophyses of Baur. The lateral processes would then 
of necessity be, as in Polypterus, diapophyses (Baur), and the 
ribs pleurapophyses or true ribs. 
Goppert states (No. 48, p. 153), based on the observations 
of Balfour and Parker, that the ribs in Lepidosteus present some 
of the characteristics of upper ribs ; and Scheel states (No. 109, 
Abstr.) that the ribs in teleosts are such ribs, and not lower 
ribs. The ribs in teleosts lie in the lining wall of the peritoneal 
cavity. If they be upper ribs they must therefore have lost 
the position assigned by origin to them, that is, in the horizontal 
