COE: NEMERTEANS OF WEST AND NORTHWEST COASTS. 157 



12. Taeniosoma mexicana Biirsrer. 

 Zool. Jabrb. Abtb. Syst., 7, p. 2B6, PI. 8, fig. G ; PI. 9, figs. 2, 3, 1893. 



This species occurs very abundanth^ on the west coasts of Panama 

 and Mexico, and at the Galapagos Islands, but has not been found 

 elsewhere. It belongs to that group of the genus having- slender 

 bodies which do not contract to any excessive amount when dis- 

 turbed or killed. The worms reach a very considerable size, those 

 one or two meters long and 5-7 mm. wide being common. Speci- 

 mens in collections often measure at least half a meter in length. 

 In shape the body is slender, flattened when strongly contracted, 

 largest just back of head ; intestinal region broad and flat ; posterior 

 extremity very slender. Snout of moderate size, distinctly marked 

 off from posterior portion of head by conspicuous lateral transverse 

 grooves which form an annular constriction when contracted. 

 Ocelli numerous, situated in an elongated cluster on each lateral 

 border of snout. 



Color dark brown, with very numerous fine white rings encircling 

 the body at irregular intervals throughout its whole length. Some 

 of the rings are vei'y much finer than others, and many are more 

 or less broken and incomplete. A large specimen has several hun- 

 dred of these rings, which remain sharp and conspicuous after the 

 worms have been kept in alcohol for many years. Snout bordered 

 laterally and anteriorly by narrow horizontal white band, which 

 passes through or immediately above terminal proboscis poi'e and 

 joins the first white ring, which occurs at junction of snout to poste- 

 I'ior portion of head. White rings commonly 1 mm. or less in 

 breadth, while alternating brown bands are about 3 mm. wide in 

 moderate extension, but are considerably narrower than diameter of 

 body. 



Habitat. — The species has previously been reported from the 

 west coasts of Panama and Mexico, and from the Galapagos Islands 

 (Burger, '93). A number of large specimens were collected by Mr. 

 Alexander Agassiz and by the Hassler expedition on the west coast 

 of Panama. Several large specimens in the Yale Museum were col- 

 lected in the same region by Mr. Bradley and another lot by Mr. 

 McNeil. It is apparently the largest and most abundant nemertean 

 foiind in that region. 



