254 



The Philippine Journal of Science 



1913 



longitudinal layer is also continuous over the terminal regions 

 although somewhat irregular in thickness, and it follows closely 

 the outline of the longitudinal layer. In the middle region its 

 condition is exactly like that described by Spengel; that is, 

 between the longitudinal bundles, the oblique fibers are gathered 

 into compact cords which bridge the intervals (fig. 2). On 

 reaching the edges of the longitudinal bundles, the oblique fibers 

 spread out f anwise, so that the middle of the longitudinal bundle 

 is covered by a complete, but thin, layer of oblique fibers. The 

 oblique fibers do not pass freely across the intervals, but lie 

 on the inner edge of extremely thin connective-tissue septa which 

 rise from the outer side of the interval (fig. 4) which, as Spengel 

 says, are like dams across the interval, separating it into a great 



number of small 4-sided 

 compartments opening 

 into the coelom between 

 the oblique bundles. 

 These "septal bands" 

 are, as Spengel says, 

 composed of the cell-poor 

 connective tissue of the 

 muscle layer, but in my 

 specimens the septal 

 bands have been found to 

 contain a few isolated 

 muscle fibers. 



The entire inner sur- 

 face, including the in- 

 tervals, the oblique mus- 

 cles, and the bands, is 

 covered by an endothe- 

 lium composed of small, rounded, irregular cells. From this 

 description it will be readily seen (1) that the body wall is 

 divided into 18 longitudinal intermuscular spaces; that is, "in- 

 tervals," by the 18 longitudinal bundles; and (2) that these 

 intervals are again divided transversely into rows of narrow 

 compartments, "stomata," by the septal bands and oblique 

 bundles. As each one of these "stomata" is connected with the 

 coelom, they are, of course, filled with the coelomic fluid, and as 

 Spengel points out the contraction of the muscles would account 

 for the small square "Buckeln der Haut" which are so charac- 

 teristic of the living animal. 



As to the function of these stomata, when we consider that 

 they are covered only by the corium and a very thin layer of 



Fig. 2. Diagram of the body wall of Thalassema griffini 

 sp. nov. ep, epidermis ; d, dermis ; cm, circular 

 muscle ; Im, longitudinal muscle in transverse section ; 

 om, oblique muscle ; sb, septal band ; ce, coelomic 

 epithelium ; st, stomata in ccelomic surface. 



