12 



PHALACEOCOBACIDJE 



PLOTUS 



a long tendon, attached anteriorly to the hsemapophysis of the 

 eighth, ninth, and tenth vertebrae. 



The action of pulling the head back preparatory to striking is 

 effected by the longus colli posterior, the actual striking movement 

 by the longus colli anterior. Another peculiarity in the organisa- 

 tion of Plotus concerns the stomach. In P. rufus, the South 

 African species, the second or pyloric portion of the stomach is 

 lined all round the opening into the duodenum by a thick coating 



Pig. 3. — Anatomy of the neck of Flolus. 1 — 12 Cervical vertebrse numbered ; 

 l.c.a. Tendon of the Longus colli anterior muscle ; l.c.p. Tendon of the Longus 

 colli posterior muscle ; D. Donitz's bridge (after Garrod). 



of hairs, while extending from near the same opening into the lumen 

 of the organ is a conical hair- covered process which evidently acts 

 as a plug or valve to close the entrance into the intestine ; the 

 details of the structure of the stomach are not the same in all the 

 species of the genus. 



Four species of this remarkable type are generally recognised, 

 spread over Africa, Madagascar, South Asia, the Malayan Islands, 

 Austraha, New Zealand, and tropical and subtropical America. 

 Only the one species, here described, is found in Africa. 



