BY N. A. COBB. 465 



the end of the tail. Each papilla is the orifice of a minute one- 

 celled gland. 



Hab. —Adults of both sexes are equally common in beach sand 

 between tide-marks on the coast of Arabia during the winter 

 months. 



Hypodontolaimus, De Man. 



H. ARABicus, n.sp. Female unknown. 



1-6 "! 1-5 2^5 T-t "'"""- The naked cuticula bears about 450 

 transverse striae, resolvable by means of the higher powers of 

 the microscope into rows of elongated dots. The neck does not 

 narrow very percei)tibly until near the head, which is truncate 

 and destitute of both setae and lips. Twelve papillae surround the 

 mouch. I saw no lateral organs but do not assert their non- 

 existence. There are no eye-spots. The shallow cyathiform 

 pharynx seems to bear at its base a ventral and a dorsal tooth. 

 The oesophagus is somewhat phalangiform, the larger and longer 

 swelling being not that which receives the pharynx but that which 

 forms the posterior termination. The central third of the ceso- 

 phagus is only one-fourth as wide as the neck. The cardiac 

 coUum is shallow but distinct. A unicellular ventral gland nearly 

 one-tliird as long as the cBso]>hagus lies in the ventral part of the 

 body cavity, just behind the cardiac region. It is unusually lai-ge, 

 being one-half as wide as the intestine, and empties its product 

 through a short duct which appears to terminate in a porus excre- 

 torius opposite to or near the cardiac collum. The nerve ring is 

 as wide as the oesophagus at the point encircled and slightly 

 oVjlique. The lateral fields are one-fourth to one-third as wide as 

 the body. The ventrally arcuate tail is conoid to the conical 

 terminus, which has a diameter one-fourth as great as the anal 

 diameter, and gives exit to the secretion of three unicellular 

 caudal glands situated opposite ^iie anus. The two equal elongated 

 cuneiform spicula have a length equal to that of the anal diameter. 

 The proximiB are not cephalated. The two accessory pieces are 

 three-fourths as long as the spicula, and are probably joined 

 together distally. The generative apparatus extends to in front of 



