A NEW SPECIES OF MONILIGASTER FROM INDIA. 379 



but very much less so tlian that of xiii, and not sufficiently 

 muscular to be called a " gizzard." There is thus a transition 

 between oesophagus and gizzard ; and it may possibly be that 

 the gut in these somites has been or is in near allies or varie- 

 ties of this species more muscular than is the case with the 

 single specimen which I have had the opportunity of examin- 

 ing ; in fact^ these regions may be potential gizzards. In 

 other species the gizzards are either more or less extensive. 



The position and extent of the gizzards appear to be one of 

 the chief specific characters of the genus, and M. indicus 

 differs from M. robustuS; A. G. B., in this point, for in 

 Bourne's species the gizzard occupies Somites xi — xv, pre- 

 sumably five in number; so that, as this is the only ana- 

 tomical feature mentioned by Dr. Bourne, and notwithstanding 

 the external resemblance with regard to the tail, I am justified 

 in creating a new species. 



There are no oesophageal glands nor other diverticula of 

 the gut. In M. japonicus Michaelsen finds that the wall of 

 the ^'oesophagus in Segments xv — xviii (?)'^ — i. e. behind the 

 gizzard — is much folded and very vascular. In the cavities of 

 the folds he found a granular mass, which " must be regarded 

 as concretions of carbonate of lime ;" but he gives no evidence 

 that this is the case. In none of the other species is any 

 mention made of the presence of lime, though of course there 

 is no reason why it should not occur. 



The " tubular intestine" immediately behind the gizzard is 

 narrow and cylindrical, remaining thus through Somites xvii 

 to about XX. It then commences to enlarge till it attains its full 

 diameter in about Somite xxx, where it occupies nearly the 

 whole width of the coelom. At each septum the " sacculated 

 intestine" is very deeply constricted, so that quite a narrow 

 neck connects the thin-walled dilated regions. 



There is no typhlosole ; the walls of the gut are very thin, 

 and provided with a dense network of longitudinal and circu- 

 larly disposed blood-vessels. 



