262 



INEZ L. WH1PPLF. 



of its fibers proceeding from the myocomma instead of the linea 

 alba. The transversalis shows about the same range of variation 

 that was described in Dieinyctylus ; the edges of its aponeurosis 

 coincide more exactly with those of the cartilage and in one very 

 muscular specimen of Amblystoma pitnctatuui, this muscle was 



strongly inserted into the cartilage 

 along the whole length of its arm. 

 In the same individual the carti- 

 lage was very large, as its arm 

 crossed the second myotome, and 

 the lateral portion of the M. ypsi- 

 loidcns anterior rose from the third 

 myocomma thus giving this muscle 

 an origin from two myocommata. 



In all of these genera as in Dic- 

 invctylns the M. pubo-ischio-femoralis 

 interims takes its origin partly from 

 the posterior end of the ypsiloid 

 cartilage. 



3. Salamaiidrina pcrspicillata. 

 This species, which, so far as is known, is the only lungless mem- 

 ber of the subfamily Mecodonta, is sufficiently different in its ab- 

 dominal musculature from the lunged forms already described, to 

 require a separate discussion. The outer, deeper portion of the 

 rectus abdominis (the rectus profundis of Maurer's nomenclature), 

 is highly specialized into a retractor of the tongue (M. pubo-hyoi- 

 deus}. It lies in a sheath, in which it moves freely, since although it 

 possesses myocommata corresponding to those of the remaining 

 portion of the rectus abdominis, these are wholly disconnected from 

 those of the main mass of somatic muscles and thus do not corre- 

 spond with the latter during all phases of muscular contraction. 

 Aside from this highly specialized region, the abdominal muscles 

 of Salamandrina are poorly developed. The external oblique 

 muscle seems reduced almost to a mere sheet of connective 

 tissue, and is evidently functional more as a support for the 

 abdominal wall than for any muscular activity. The internal 

 oblique I have been unable to demonstrate. The rectus abdomi- 

 anis is thin and its two halves are separated by a very wide line 



I'"IG. 4. Ventral view showing 

 the ypsiloid apparatus of Anihly- 

 stoma punctatnin, X 2 - Dissection 

 and abbreviations as in Fig. 2. 



