ECHIUROID FAUNA OF NORTH PACIFIC — FISHER 483 



Remarks.— Ih^ type of this genus is the species from Green Turtle 

 Bay, off Great Abaco Island, Bahamas, which Charles B. Wilson 

 (1900, p. 176) erroneously identified as Ochetostoma erythrogrammon 

 Leuckart and Kiippell and which Wilhelm Fischer (1926, p. 110) 

 named Listriolohus hahamensis. The generic name derives from 

 Spengel (1912, p. 316), who pointed out the peculiarity of the muscle 

 bands but neglected to designate a species with a valid name, men- 

 tioning only Thalassema erythrogrammon of Sluiter (1883) and of 

 Wilson (1900), neither being true erythrogrammon (the type of 

 Ochetostoma) . 



I designated Z. hahamensis as the type (1946, p. 233). Wilson's 

 specimen was 160 mm. long, including proboscis 30 mm., and 24 mm. 

 in greatest diameter. Longitudinal muscle bands 16, about 1.5 mm. 

 wide, with interspaces 4.5 to 7 mm. wide at middle of body. There 

 were three pairs of nephridia enormously swollen and packed with 

 sperm. The anterior pair opened 3 mm. in front of the setae and all 

 three pairs were furnished with spirally coiled nephrostome lips. 

 Anal glands, 90 mm. long and without visible funnels. Interbasal 

 muscle of setae not mentioned. 



I have examined a small, contracted specimen from Cayo Cristo, 

 Cuba (American Museum of Natural History), which is probably 

 L. hahamensis. It is only 20 mm. long, lacks a proboscis, and the 

 muscle bands are not all clearly defined, but it agrees with Wilson's 

 description in essentials. There are three pairs of nephridia, the an- 

 teriormost just in front of the setae, which are enveloped by a cone of 

 muscle without obvious separated fascicles of muscle. There is no 

 interbasal muscle. The foregut is close to the nerve cord so that the 

 ventral mesentery is poorly developed. The pho.rynx is thin walled 

 and esophagus long, but the gizzard and stomach can not be iden- 

 tified on account of poor preservation. The neurointestinal vessel is 

 double but unites before joining ventral vessel. At the dorsal end 

 each branch seems to join directly the dorsal vessel, a definite ring 

 vessel not being apparent. The anal vesicles are very long and there 

 is a coecum in front of the large cloaca. 



In his revision. Bock (1942) gave Listriolohus at best only subge- 

 neric rank under Ochetostoma.^ but L. pelodes Fisher (1946) with two 

 pairs of nephridia and eight muscle bands was not then known. 

 Now the discovery of a new, well-marked species with only one pair 

 of nephridia and six muscle bands greatly strengthens the position of 

 Listriolohus as a group of generic stature. 



