188 WILLIAM F. ALLEN 



14. The motor and sensory innervation of the M. cordis 

 caudahs is from branches of certain of the neighboring ventral 

 spinal rami. Two reconstructions showed a large cephalic 

 branch from one of the last ventral motor nerves crossing the M. 

 cordis caudalis or from the last nerve behind it, as passing along 

 the inner surface of the M. cordis caudalis for some distance. 

 It doubtless furnished a large part of the motor supply for this 

 muscle. 



15. Some seven or eight muscle spindles were found in con- 

 nection with some very large muscle fibers in the ventro-cephalic 

 portion of the M. cordis caudalis. Most of these spindles were 

 enclosed in a well-developed lamellated connective tissue capsule, 

 and were apparently supplied from branches of the first ventral 

 spinal rami that cross the muscle. 



16. Certain very large axones were seen in transverse section 

 of the rami ventralis of Polistotrema. They were supposed to 

 be axones of the giant cells of the spinal cord. 



LITERATURE 



Abel, W. 1912 Further observations on the development of the sympathetic 



system in the chick. Jour. Anat. Physiol., London, vol. 47. 

 Ahlborn, F. 1884 Ueber den LTrsprung und Austritt der Hirnnerven von 



Petromyzon. Zeitschr. f. wiss. Zool., Bd. 40. 

 Alcock, R. 1898 The peripheral distribution of the cranial nerves of Ammo- 



ccEtes. Jour. Anat. Physiol., London. 

 Allen, W. F. 1916 Studies on the spinal cord and medulla of cyclostomes 



with special reference to the formation and expansion of the roof 



plate and the flattening of the spinal cord. Jour. Comp. Neur., vol. 



26. 

 Allis, E. P. 1897 The cranial muscles and cranial and first spinal nerves in 



Amia calva. Jour. Morph., vol. 12. 

 Ayers, H. 1908 The ventricular fibers of the brain of my.xinoids. Anat. 



Anz., Bd. 32. 

 Ayers, H. and Worthington, J. 1907 The skin end-organs of the trigeminus 



and lateral nerves of Bdellostoma dombeyi. Am. Jour. Anat., vol. 7. 



1908 The finer anatomy of the brain of Bdellostoma dombeyi. Am. 



Jour. Anat., vol. 8. 

 Balfour, F. M. 1880 On the spinal nerves of Amphioxus. Quart. Jour. 



Micr. Sci. Also chap. 18, Memorial Edition, London, 1885. 



1885 The works of Francis Maitland Balfour, vol. 1, London. 

 Beard, J. 1888 The development of the peripheral nervous system of verte- 

 brates. Quart. Journ. Micr. Sci., vol. 29. 



