140 Proceedings of the Royal Irish Academy. 



Tubifex Thompsoni n. sp.^ 

 Plate IX., fig. 7, A-c. 



These worms are of a bright-red colour. The length is about 20 mm. 

 The anterior dorsal setas (PI. ix., fig. 7, a) closely resemble those of 

 T. costatus. They are found in segments 5-18, whilst those of 

 T. costatus only occur in segments 5-13. There are 7-10 of them 

 in a bundle. The remaining dorsal bundles contain ouly bifid setae, 

 having two equal teeth. In segments 2-4 there are 3 or 4 in each bundle ; 

 behind the 18th segment there are only 2 in a bundle. The ventral 

 bundles contain 3-5 bifid setae. In the anterior bundles the teeth are 

 nearly equal ; but further back the lower tooth becomes smaller. The 

 brain (fig. 7, b) is concave in front and behind. The nephridia are large, 

 without a covering of bladder-like cells; and the cavity of the duct is 

 swollen into a sac near the external pore. The spermatheca is sac-shaped 

 and long, extending into the 9th segment. The sperm-duct terminates 

 in a chitinous penis-sheath of characteristic shape (fig. 7, c). The proximal 

 half is broad and cylindrical, whilst the distal half is narrow and curved. 

 I^ear the external pore there is a sac containing a nail-shaped penial seta. 

 This apparatus is quite different from the penis-sheath of T. costatus, and 

 easily serves to distinguish the species from all others. 



Mature — February. 



Habitat — Ireland. Eock-pools at Howth, Co. Dublin. 



Tubifex Templetoni n. sp.^ 

 Plate VIII., fig. 6, A-F. 



This is a very small species of Tubifex, being only 10-14 mm. long. It 

 is pink in colour, and of a soft consistency. The anterior dorsal bundles 

 contain 3-4 bifid and 1-4 capilliform set£e. These anterior bifid setae 

 (PL VIII., fig. 6, A, a) have three fine intermediate teeth. The capilliform sette 

 are very thin and flexible. The ventral bundles have 3-4 setae. The upper lip 

 is longer and thinner than the lower one (fig. 6, A, b). There are no ventral 

 setae in the 11th segment, and no genital setae are present. The girdle occupies 

 segments 11 and 12, and is formed of cells with very granular contents. The 

 front segments are formed of a narrow anterior, and a broad posterior ring. 



1 This species is dedicated to William Thompson, the well-known Irish naturalist, author of 

 " The Natural History of Ireland." 



- This species is dedicated to John Templeton, of Belfast, who, with his son, Rohert Templeton, 

 was one of the earliest students uf the Annelida. 



