No. 2.] AMPHIUMA MEANS. 389 



the early part of this communication, the trunk muscles are 

 separated into two regions, viz., the dorsal and abdominal, by 

 the fascial lamina split off from the external dorsal sheath. 

 This lamina extends through the wall to the body cavity. A 

 similar disposition of the fascia occurs in Crypt obranchus japo- 

 niciis, van der Hoeven, as described by Humphrey (11). The 

 dorsal mass of AvipJimma is not differentiated into separate 

 muscles, but for the sake of convenience may be considered 

 as composed of two parts : the superior, lying above the trans- 

 verse processes, and the inferior, lying beneath these processes. 

 The former corresponds to the erector spinae of some authors. 

 The latter is called rectus trunci internus by Schmidt, Goddard 

 and van der Hoeven in a description of other Amphibia of 

 this order. Mivart (12) speaks of a similar muscle in Meno- 

 poma as being a part of the retrahens costarum. The anterior 

 portion of this muscle in Amphhnna undoubtedly functions as 

 a retrahens costarum, being attached to the minute ribs found 

 on the first seven or eight vertebrae of the trunk. The skin 

 having been carefully removed from the back, and the muscles 

 well stained and macerated by the fluid mentioned previously, 

 there will be seen lying along the axis longitudinally-disposed 

 rows of cones, the enveloping fascia of which appears, at first 

 sight to form a kind of network. 



In the superior dorsal mass there are three rows of cones 

 lying side by side. The apices of the row adjacent to the 

 axis are directed posteriorly, those of the next row anteriorly, 

 and those of the third row posteriorly. TJius it is seen that the 

 apical direction of the cones varies alternately in the different 

 rows. Each cone is introduced into the preceding one about 

 one-third of its length, as shown in Fig. 10. 



From the exterior apex of each cone in the two distal rows 

 a tendinous cord extends to the interior apex of the following 

 cone, thus serving to hold the apices in position. The row 

 most distant from the axis has the deep part of the base of 

 each cone firmly attached to the outer half of a transverse 

 process. That part of the base distal from the axis is reflected 

 to form an inscriptio tendinea extending transversely to the 

 mid-ventral line. The superficial base of the cone blends with 



