THE ANATOMY OF SCALIBKEGMA INFLATUM. 255 



by a dorsal incision. The coelom is spacious, especially in the 

 inflated portion of the animal. It is subdivided anteriorly 

 by four diaphragms or septa placed transversely at the level 

 of the posterior end of each of the four branchiferous 

 segments. PJach diaphragm is inserted at the level of the 

 hinder border of the annulus which immediately follows the 

 chastigerous annulus. The second, third, and fourth dia- 

 phragms are perforated by the minute funnels of the first 

 three nephridia. 



Behind the branchial region the coelom is not subdivided by 

 transverse partitions, but is continuous to the posterior end of 

 the animal. In the post-branchial portion of the body each 

 of the segmentally arranged blood-vessels is accompanied by a 

 small strand of connective tissue, which near the nephrostome 

 spreads out slightly and is attached to the body-wall a little 

 above the level of the neuropodium. The gonads are 

 developed near the nephrostome on the surface of the expanded 

 portion of this strand (fig. 21). These narrow bands are 

 the equivalents of the septa of the branchial region and of 

 other Annelids, such as Arunicola grubii and A. ecaudata, 

 in which the transition from the narrow bands to complete 

 septa is well seen (Gamble and Ashworth, IDOO, pi. 25, tigs. 

 44, 45). 



The stomach and intestine are loosely bound to the mid- 

 ventral body-wall by numerous thin strands of muscular 

 tissue, which form an imperfect ventral mesentery. Just as in 

 Arenicola (Gamble and Ashworth, 1898, p. 14) the stomach 

 is probably swung backwards and forwards by the movement 

 of the body, thus bringing about a thorough mixing of the 

 sand, etc., with the secretion of the oesophageal pouches and 

 of the stomach ; the muscle strands forming the incomplete 

 ventral mesentery allow a certain amplitude of swing, as the 

 drawing of the dissection shows. In the specimen, the pi'o- 

 boscis of which is strongly retracted, the stomach is probably 

 drawn backwards to its most posterior position, as is shown 

 by the backward trend of the blood-vessels. 



The intestine is probably moveable in a similar manner, but 



