189G.] rnoM tub sandwich islands. 207- 



Tliere are no r/enital papillci!. 



The first distinct septum separates segment iv. from v. This 

 and the three following — in fact all the septa wliioh lie in front of 

 the gizzard — are strengthened not only by an increased thickness, 

 but b}' nniscnlar strands which bind septum to septum and to the 

 body-wall. Following the gizzard are four thickened septa, of 

 which the last bounds the thirteenth segment posteriorly ; here 

 also are a few muscular threads passing between the septa and 

 from them to the body-walls. Tiiese threads are found as far 

 back as the septum lying between xv. and xvi. As is so often tlie 

 ease, these bands arise from one segment and traverse aiiotlier to 

 be attached to the septum behind it or to the body-wall between. 

 The direction of the muscular strands is outwards. Two particu- 

 larly strong muscular bands — one on either side and latero-dorsal in 

 position— attach the gizzard to the septum next following. 



The gizzard is round iu form — neither particularly elongated 

 nor bell-shaped. 



The intestine begins suddenly in the xvth segment; the cseca 

 are simple and conical in form, extending through three segments. 



The last heart is in segment siii. 



The large sperm-sacs are as usual in the xith and xiith segments. 



The spermiducal r/lands are large and loosish in texture, owing 

 to their extensive lobulation. They extend through segments xvii. 

 to xxi. inclusive. The duct is moderately long and bent into a 

 curved horseshoe. 



The spermathecce are four pairs lying in segments vi.-ix. ; the 

 point itself is oval, with a tendency to be pointed at the tip ; the 

 duct is short. The diverticulum is longer than the pouch and 

 nioniliform distally. 



There are egg-sacs in segments xiii.-xiv. 



Hah. Trinidad. 



§ Tlie Distribution of PerichsBta. 



Except for accidental transference to this country and to other 

 tempeiate climates, the genus Perichmta is purely tropical in its 

 range, and is practically confined to the Oriental region and to the 

 Neotropical ; from the former it reaches the Australian part of the 

 Eastern Archipelago and the continent of Australia itself. Africa 

 has no true Pericliasta, except P. eapensis, which is also Oriental. 

 In all parts of the Oriental region Perichccta is a dominant form, and 

 always constitutes a large proportion of the gatherings of worms 

 from such localities. It is also exceedingly abundant in some of 

 of the AVest Indian Islands, such as Trinidad, Bahamas, Grenada, 

 Jamaica, Bermudas, and Barbados. It occurs more rarely upon 

 the South American Continent. The following species are already 

 known to occur in both the Old and the New AVorlds : — P. indica, 

 P. sumatrana, P. houlleti, P. dyeri, and P. posthuma. Peculiar to 

 the New World, so far as published records go, are P. sancti jacohi', 

 P. ringeana, P. elongata, P. pallida, P. hevmudensis, P. barbadensis, 



