vui, D, 4 Wharton: Some Philippine Thalassemx 253 



and some points have been noted which he does not bring out in 

 hia. description. In T. griffini the dermal muscle layer consists 

 of four parts. The first of these is a single layer of muscle cells 

 lying at the base of the dermis, which runs in a longitudinal 

 direction and covers the body throughout, completely separating 

 the corium from the deeper muscle layers. This layer is so 

 thin that it is very difficult to see in cross sections of the body 

 wall, but it is easily found by peeling off the corium in glycerine 

 and then examining with the microscope. On account of its 

 position and relations to the surrounding parts, I have called 

 it the external limiting muscle. Within the external limiting 

 muscle are the three regular muscular layers — the circular or 

 ring muscle, the longitudinal muscle, and the oblique muscle. 



In order to make clear the relations between these muscles, 

 it will be necessary to describe the middle or longitudinal layer 

 first. In the two terminal regions which have been mentioned, 

 the longitudinal muscle forms a thick continuous sheet without 

 any separation whatever into bundles (fig. 5). At about 1 cm. 

 from each end, this sheet gradually becomes separated into 18 

 large longitudinal bundles. In cross section these bundles have 

 the shape of a more or less regular isosceles triangle with the 

 base lying against the inner oblique layer and the apex turned 

 outward. Between the bundles are the "intervals" of which 

 Spengel speaks. He says that in Riippell's specimen of T. ery- 

 throgrammon a very thin, but continuous, layer of longitudinal 

 muscle continues across the intervals from the apex of one bundle 

 to the next. In Thalassema griffini traces of this layer may be 

 found, but in place of the continuous layer of which Spengel 

 speaks it is broken up into small bundles of fibers and these 

 bundles are scattered across the interval. These little bundles 

 rarely consist of more than 10 muscle fibers, and they are in 

 almost all cases separated by a space greater than the width 

 of the bundles and in some cases the space between them may 

 be as wide as half the whole interval. They are surrounded by 

 connective-tissue fibers and overlaid by the endothelium (fig. 3). 



The circular muscle on the outside of the longitudinal muscle 

 is a continuous sheet in the terminal regions, about half the 

 thickness of the longitudinal layer. In the middle region of the 

 body the circular layer also changes in character. It becomes 

 much thinner, and is spread out flat over the large longitudinal 

 bundles, but over the intervals between them it is drawn together 

 more or less to form bundles which are connected by a very 

 thin layer of fibers. 



The oblique or diagonal muscle on the inner side of the 



